Circles Application

What is the equation of the circle?

• (x+1)² + (y +1)² = 3

• (x+1)² + (y -1)² = 3

• (x+1)² + (y +1)² = 9

• (x-1)² + (y -1)² = 9

A circle's equation is (x-1)² + y² = 25. What is the area of the circle?

• 25

• 25π

• 12.5

• 12.5π

A circle's equation is (x+1)² + (y-2)² = 4. What is the circumference of the circle?

• 4

• 4π

• 2

• 2π

What is the equation of a circle whose diameter is 24 and whose center is at the origin?

• x²+y²=125

• x²+y²=64

• x²+y²=144

• x²+y²=576

The point (-5,6) is on a circle whose center is at (-1,3). Write the equation of the circle.

• (x+1)² + (y-3)²= 4000

• (x+5)² + (y-0)²= 25

• (x+1)² + (y-3)²= 25

Find the center of a circle if the endpoints of one of its diameters are at (-12, -7) and (3, 5).

• (-4.5, -1)

• (-7.5, -6)

• (4.5, 1)

• (7.5, 6)

The diameter of a flying disc is 10 inches. Find the circumference of the disc. Use 3.14 as an approximation for π.

• A.) 3.14 inches

• B.) 31.4 inches

• C.) 314 inches

• D.) 0.314 inches

A rotating water sprinkler sprays water is a circular motion. The sprinkler has a radius of 7.5ft that it can reach. Determine the circumference of this water sprinkler's range.

• C = pi x d

  C = 3.14 x 7.5

  C = 23.55 ft

• C = pi x 2 x r

  C = 3.14 x 2 x 7.5

  C = 47.1 ft

• C = pi x d

  C = 3.14 x 7.5

  C = 10.65 ft

• C = pi x 2 x r

  C = 3.14 x 2 x 7.5

  C = 18.14 ft

Abby has a circular walking path around her house. She looked on a map, and saw that the diameter was about 300 ft. If she walks around the path 4 times, how far would she have walked?

• C = pi x d

  C = 3.14 x 300

  4 x Circumference = 4 x 942

  She walked 1,884 ft.

• C = pi x 2 x r

  C = 3.14 x 600

  4 x Circumference = 4 x 942

  She walked 7,536 ft.

• C = pi x d

  C = 3.14 + 300

  4 x Circumference = 4 x 303.14

  She walked 1,212.56 ft.

The tire of a car has a radius of 10.5 inches. How far can the tire travel if it completes 1 full rotation. [Circumference]. Use ²²/₇ as an approximation for π.

• a.) 22 inches

• b.) 33 inches

• c.) 44 inches

• d.) 66 inches