Math · Drill 21

Math practice 21

91 questions ~15 min recommended

⏱ 00:00

Score

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1. What is the area of a circle with diameter $10$ inches?

A. $$10\pi$

B. $$50\pi$

C. $$100\pi$

D. $$25\pi$

2. What is the area of sector with central angle 120° in a circle with radius 8?

A. $$\frac{128\pi}{3}$

B. $$\frac{32\pi}{3}$

C. $$\frac{64\pi}{3}$

D. $$\frac{64\pi}{6}$

3. On a coordinate plane, a circle has equation $(x+1)^2+(y-4)^2=64$. What is the radius of the circle?

A. $$16$

B. $$64$

C. $$8$

D. $$4$

4. Find the area of a circle with radius 7.

A. $$14\pi$

B. $$28\pi$

C. $$49\pi$

D. $$21\pi$

5. What is the area of a circle with radius 12?

A. $$24\pi$

B. $$36\pi$

C. $$144\pi$

D. $$72\pi$

6. If the circumference of a circle is $20\pi$, what is its radius?

A. 5

B. 10

C. 15

D. 20

7. What is the radius of a circle if the circumference is $16\pi$?

A. 4

B. 8

C. 16

D. 32

8. A circle has an area of $64\pi$. What is its diameter?

A. 8

B. 12

C. 16

D. 32

9. A circle has radius $5$. What is the area of the circle?

A. $$10\pi$

B. $$25\pi$

C. $$5\pi$

D. $$50\pi$

10. A circle has a diameter of 20. What is the area of the circle?

A. $$100\pi$

B. $$300\pi$

C. $$200\pi$

D. $$400\pi$

11. Which equation represents a circle with center (3, -4) and radius 5?

A. $$(x + 3)^2 + (y - 4)^2 = 25$

B. $$(x - 3)^2 + (y + 4)^2 = 25$

C. $$(x - 3)^2 + (y + 4)^2 = 5$

D. $$(x - 3)^2 + (y - 4)^2 = 5$

12. What is the radius of a circle if the area is $64\pi$?

A. 4

B. 8

C. 16

D. 32

13. A circle has a radius of 6 centimeters. What is the area, in square centimeters, of a sector of this circle that has a central angle of $\dfrac{2\pi}{3}$ radians?

A. $$24\pi$

B. $$36\pi$

C. $$12\pi$

D. $$4\pi$

14. The equation of a circle is $(x+1)^2+(y-4)^2=64$. What is the circumference of the circle?

A. $$128\pi$

B. $$64\pi$

C. $$16\pi$

D. $$8\pi$

15. Which equation represents a circle with center $(2,-3)$ and radius $5$?

A. $$(x-2)^2+(y+3)^2=25$

B. $$(x-2)^2+(y+3)^2=5$

C. $$(x+2)^2+(y-3)^2=25$

D. $$(x-2)^2+(y-3)^2=25$

16. What is the length of the arc with a central angle of 45° in a circle with radius 7?

A. $$\frac{14\pi}{8}$

B. $$\frac{14\pi}{3}$

C. $$\frac{7\pi}{4}$

D. $$\frac{7\pi}{2}$

17. A circle is given by the equation $(x-4)^2+(y+1)^2=64$. What is the radius of the circle?

A. $$64$

B. $$8$

C. $$4$

D. $$16$

18. What is the area of a circle with radius 3?

A. $$6\pi$

B. $$3\pi$

C. $$9\pi$

D. $$12\pi$

19. What is the area of a circle with diameter 14?

A. $$98\pi$

B. $$49\pi$

C. $$196\pi$

D. $$28\pi$

20. Which equation represents a circle with center (0, 0) and radius 10?

A. $$(x-10)^2 + y^2 = 100$

B. $$x^2 + y^2 = 100$

C. $$(x+10)^2 + y^2 = 10$

D. $$x^2 + y^2 = 10$

21. A circle has area $81\pi$ square units. What is the radius of the circle?

A. $$\frac{81}{\pi}$

B. $$\sqrt{81\pi}$

C. $$18$

D. $$9$

22. Which equation represents a circle with center (-4, 5) and radius 6?

A. $$(x-4)^2 + (y+5)^2 = 36$

B. $$(x-4)^2 + (y-5)^2 = 6$

C. $$(x+4)^2 + (y+5)^2 = 6$

D. $$(x+4)^2 + (y-5)^2 = 36$

23. If the circumference of a circle is $30\pi$, what is its area?

A. $$225\pi$

B. $$100\pi$

C. $$225\pi^2$

D. $$150\pi$

24. The circumference of a circle is $16\pi$ centimeters. What is the area of the circle, in square centimeters?

A. $$256\pi$

B. $$64\pi$

C. $$16\pi$

D. $$8\pi$

25. The equation $x^2 + y^2 - 6x + 8y = 0$ represents a circle in the standard $(x, y)$ coordinate plane. What is the radius of this circle?

A. 5

B. 10

C. 14

D. 25

26. In a circle with center $O$, a central angle has a measure of $60°$. If the radius of the circle is 6 centimeters, what is the length, in centimeters, of the minor arc intercepted by this central angle?

A. $$\pi$

B. $$2\pi$

C. $$3\pi$

D. $$6\pi$

27. In the standard $(x, y)$ coordinate plane, how many points lie on both the circle $x^2 + y^2 = 25$ and the line $x = 0$?

A. 0

B. 1

C. 2

D. 4

28. The area of a circle is $49\pi$ square centimeters. What is the circumference of the circle, in centimeters?

A. $$14\pi$

B. $$7\pi$

C. $$98\pi$

D. $$24.5\pi$

29. The equation of a circle in the standard $(x, y)$ coordinate plane is $x^2 + y^2 - 10x + 6y + 18 = 0$. What is the radius of the circle?

A. $$8$

B. $$4$

C. $$\sqrt{52}$

D. $$16$

30. Which equation represents a circle with center $(0,5)$ and radius $12$?

A. $$x^2+(y-5)^2=12$

B. $$x^2+(y+5)^2=144$

C. $$(x-5)^2+y^2=144$

D. $$x^2+(y-5)^2=144$

31. A circle has radius $11$. What is the circumference of the circle?

A. $$22\pi$

B. $$121\pi$

C. $$44\pi$

D. $$11\pi$

32. A circle has diameter $10$. What is the area of the circle?

A. $$50\pi$

B. $$100\pi$

C. $$10\pi$

D. $$25\pi$

33. Which equation represents a circle with center $(-4,1)$ and radius $3$?

A. $$(x+4)^2+(y-1)^2=9$

B. $$(x-4)^2+(y+1)^2=9$

C. $$(x-4)^2+(y+1)^2=3$

D. $$(x+4)^2+(y-1)^2=3$

34. A circle has circumference $18\pi$. What is the diameter of the circle?

A. $$9$

B. $$18$

C. $$6$

D. $$36$

35. A sector of a circle has radius $9$ and central angle $120^\circ$. What is the area of the sector?

A. $$81\pi$

B. $$18\pi$

C. $$54\pi$

D. $$27\pi$

36. A circle has diameter $12$. What is the area of the circle?

A. $$72\pi$

B. $$144\pi$

C. $$12\pi$

D. $$36\pi$

37. What is the measure of the arc AB with central angle 45° in a circle with radius 7?

A. $$\frac{14\pi}{2}$

B. $$\frac{7\pi}{2}$

C. $$\frac{7\pi}{4}$

D. $$\frac{14\pi}{4}$

38. What is the area of sector with central angle 45° in a circle with radius 10?

A. $$25\pi$

B. $$50\pi$

C. $$\frac{50\pi}{8}$

D. $$\frac{25\pi}{2}$

39. What is the equation of a circle with center (0, 0) and radius 8?

A. $$x^2 + y^2 = 8$

B. $$(x - 8)^2 + (y - 8)^2 = 64$

C. $$(x - 8)^2 + (y + 8)^2 = 8$

D. $$x^2 + y^2 = 64$

40. What is the area of a circle with radius 11?

A. $$44\pi$

B. $$132\pi$

C. $$22\pi$

D. $$121\pi$

41. Find the circumference of a circle with radius 14.

A. $$42\pi$

B. $$56\pi$

C. $$28\pi$

D. $$14\pi$

42. Which equation represents a circle with center (3, -2) and radius 5?

A. $$(x-3)^2 + (y+2)^2 = 25$

B. $$(x+3)^2 + (y+2)^2 = 5$

C. $$(x-3)^2 + (y-2)^2 = 5$

D. $$(x+3)^2 + (y-2)^2 = 25$

43. A circle is represented by $(x + 1)^2 + (y - 2)^2 = 49$. What is the radius?

A. 3.5

B. 7

C. 14

D. 49

44. What is the measure of the arc with a central angle of 120° in a circle with radius 3?

A. $$3\pi$

B. $$4\pi$

C. $$6\pi$

D. $$2\pi$

45. Which equation represents a circle with center (7, 8) and radius 9?

A. $$(x - 7)^2 + (y - 8)^2 = 81$

B. $$(x - 7)^2 + (y + 8)^2 = 9$

C. $$(x - 7)^2 + (y - 8)^2 = 9$

D. $$(x + 7)^2 + (y + 8)^2 = 81$

46. In a circle of radius $10$, arc $\overset{\frown}{AB}$ is subtended by a central angle of $90^\circ$. What is the length of arc $\overset{\frown}{AB}$?

A. $$10\pi$

B. $$5\pi$

C. $$20\pi$

D. $$\dfrac{5\pi}{2}$

47. A circle has radius $7$. What is the circumference of the circle?

A. $$49\pi$

B. $$14\pi$

C. $$7\pi$

D. $$98\pi$

48. In a circle of radius $4$, arc $\overset{\frown}{EF}$ is subtended by a central angle of $135^\circ$. What is the length of arc $\overset{\frown}{EF}$?

A. $$6\pi$

B. $$\dfrac{8\pi}{3}$

C. $$3\pi$

D. $$\dfrac{3\pi}{2}$

49. Which equation represents a circle with center $(2,-3)$ and radius $5$?

A. $$(x+2)^2+(y-3)^2=5$

B. $$(x+2)^2+(y-3)^2=25$

C. $$(x-2)^2+(y+3)^2=5$

D. $$(x-2)^2+(y+3)^2=25$

50. A circle has diameter $14$. What is the circumference of the circle?

A. $$14\pi$

B. $$49\pi$

C. $$28\pi$

D. $$7\pi$

51. A circle has radius $6$. What is the area of the circle?

A. $$12\pi$

B. $$18\pi$

C. $$36\pi$

D. $$6\pi$

52. What is the length of arc AB with central angle 60° in a circle with radius 5?

A. $$\frac{10\pi}{3}$

B. $$\frac{5\pi}{3}$

C. $$\frac{5\pi}{2}$

D. $$\frac{5\pi}{6}$

53. A circle has circumference $30\pi$ cm. What is the radius of the circle?

A. $$60$

B. $$15$

C. $$\frac{30}{\pi}$

D. $$30$

54. If a circle has a circumference of $20\pi$, what is its radius?

A. 5

B. 10

C. 15

D. 20

55. What is the length of arc AB with central angle 120° in a circle with radius 6?

A. $$8\pi$

B. $$12\pi$

C. $$6\pi$

D. $$4\pi$

56. A circle has radius $6$ ft. What is the area of the circle?

A. $$72\pi$

B. $$18\pi$

C. $$36\pi$

D. $$12\pi$

57. A circle has area $49\pi$. What is the radius of the circle?

A. $$14$

B. $$\dfrac{49}{2}$

C. $$7$

D. $$49$

58. A circle has circumference $18\pi$ meters. What is the diameter of the circle?

A. $$18$

B. $$9$

C. $$\frac{18}{\pi}$

D. $$36$

59. Which equation represents a circle with center $(2,-3)$ and radius $5$?

A. $$(x+2)^2+(y-3)^2=25$

B. $$(x-2)^2+(y+3)^2=5$

C. $$(x-2)^2+(y+3)^2=25$

D. $$(x-2)^2+(y-3)^2=25$

60. The area of a circle is $81\pi$ square units. What is the radius of the circle?

A. $$9$

B. $$81$

C. $$18$

D. $$\frac{81}{2}$

61. A circle has diameter $10$. What is the area of the circle?

A. $$10\pi$

B. $$25\pi$

C. $$100\pi$

D. $$50\pi$

62. A sector of a circle has radius $10$ and area $25\pi$. What is the measure of the sector's central angle?

A. $$180^\circ$

B. $$45^\circ$

C. $$60^\circ$

D. $$90^\circ$

63. A circle has diameter $12$ units. What is the area of the circle?

A. $$72\pi$

B. $$12\pi$

C. $$36\pi$

D. $$144\pi$

64. Which equation represents a circle with center $(3,-2)$ and radius $5$?

A. $$(x-3)^2+(y+2)^2=25$

B. $$(x-3)^2+(y-2)^2=25$

C. $$(x+3)^2+(y-2)^2=25$

D. $$(x-3)^2+(y+2)^2=5$

65. A circle has circumference $30\pi$. What is the diameter of the circle?

A. $$\dfrac{30}{\pi}$

B. $$30$

C. $$60$

D. $$15$

66. A circle has radius $6$. What is the circumference of the circle?

A. $$36\pi$

B. $$12\pi$

C. $$24\pi$

D. $$6\pi$

67. A sector of a circle has radius $8$ inches and central angle $90^\circ$. What is the area of the sector?

A. $$16\pi$

B. $$128\pi$

C. $$8\pi$

D. $$64\pi$

68. In a circle with radius $10$ m, arc $AB$ subtends a central angle of $45^\circ$. What is the length of arc $AB$?

A. $$\frac{20\pi}{45}$

B. $$\frac{5\pi}{4}$

C. $$\frac{5\pi}{9}$

D. $$\frac{5\pi}{2}$

69. In the coordinate plane, a circle is given by $(x+1)^2+(y-4)^2=36$. What is the radius of the circle?

A. $$3$

B. $$36$

C. $$\sqrt{36\pi}$

D. $$6$

70. What is the circumference of a circle with radius 11?

A. $$33\pi$

B. $$55\pi$

C. $$22\pi$

D. $$44\pi$

71. Calculate the circumference of a circle with radius 15.

A. $$60\pi$

B. $$30\pi$

C. $$45\pi$

D. $$15\pi$

72. Which equation represents a circle with center (-5, 5) and radius 6?

A. $$(x - 5)^2 + (y + 5)^2 = 6$

B. $$(x - 5)^2 + (y + 5)^2 = 36$

C. $$(x + 5)^2 + (y - 5)^2 = 36$

D. $$(x + 5)^2 + (y - 5)^2 = 6$

73. What is the length of arc AB if the circle's radius is 8 and the central angle is 90°?

A. $$16\pi$

B. $$4\pi$

C. $$8\pi$

D. $$2\pi$

74. Find the radius of a circle with an area of $81\pi$.

A. 6

B. 9

C. 18

D. 27

75. A circle is defined by $(x - 2)^2 + (y + 3)^2 = 16$. What is the radius of the circle?

A. 2

B. 3

C. 4

D. 5

76. A circle has a radius of 12. What is the area of the circle?

A. $$144\pi$

B. $$36\pi$

C. $$48\pi$

D. $$24\pi$

77. Which equation represents a circle with center $(2,-3)$ and radius $5$?

A. $$(x-2)^2+(y+3)^2=25$

B. $$(x-2)^2+(y+3)^2=5$

C. $$(x+2)^2+(y-3)^2=25$

D. $$(x-2)^2+(y-3)^2=25$

78. A circle has area $64\pi$. What is the radius of the circle?

A. $$8$

B. $$4$

C. $$32$

D. $$16$

79. A circle has diameter $14$. What is the area of the circle?

A. $$98\pi$

B. $$196\pi$

C. $$14\pi$

D. $$49\pi$

80. A circle in the coordinate plane is given by $(x+1)^2+(y-4)^2=49$. What is the radius of the circle?

A. $$\sqrt{49\pi}$

B. $$49$

C. $$14$

D. $$7$

81. A circle has a radius of 4. What is the length of an arc with a central angle of 180°?

A. $$6\pi$

B. $$2\pi$

C. $$4\pi$

D. $$8\pi$

82. The area of a circle is $49\pi$ square units. What is the radius of the circle?

A. $$14$

B. $$7$

C. $$49$

D. $$\sqrt{49\pi}$

83. What is the radius of a circle with an area of $49\pi$?

A. 7

B. 14

C. 24.5

D. 49

84. A circle has circumference $30\pi$ cm. What is the diameter of the circle?

A. $$15$ cm

B. $$30$ cm

C. $$10$ cm

D. $$60$ cm

85. A circle has area $81\pi$. What is the diameter of the circle?

A. $$9$

B. $$\dfrac{81}{2}$

C. $$18$

D. $$81$

86. A circle has diameter $12$ inches. What is the area of the circle?

A. $$72\pi$

B. $$12\pi$

C. $$144\pi$

D. $$36\pi$

87. What is the area of a circle with radius 9?

A. $$81\pi$

B. $$27\pi$

C. $$18\pi$

D. $$162\pi$

88. A circle has area $16\pi$. What is the radius of the circle?

A. $$4$

B. $$16$

C. $$2$

D. $$8$

89. In a circle with center $O$, a central angle has a measure of $60°$. If the radius of the circle is 6 centimeters, what is the length, in centimeters, of the minor arc intercepted by this central angle?

A. $$2\pi$

B. $$6\pi$

C. $$\pi$

D. $$3\pi$

90. The circumference of a circle is $16\pi$ centimeters. What is the area of the circle, in square centimeters?

A. $$16\pi$

B. $$64\pi$

C. $$256\pi$

D. $$8\pi$

91. The equation $x^2 + y^2 - 6x + 8y = 0$ represents a circle in the standard $(x, y)$ coordinate plane. What is the radius of this circle?

A. 5

B. 10

C. 14

D. 25

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