Circle Review

Use the vocabulary listed to label the parts of a circle.

b

d

e

f

g

h

i

c

a

radius

tangent

sector

diameter

circumference

segment

Arc

secant

chord

David, Daniel, and Avery are planning to build a mini dog park in their backyard. They want to put a fence around the circular park. Can you help them figure out the formula to calculate the length of the fence?

• 2πr

• πd

The _____ is the distance from the center to any point on the circle.

Ashley, and Emma are having a fun day in the circular pool outside. They noticed that the pool has a radius of r meters. Can you help them figure out the formula to calculate the area of this pool?

• A = 2πr

• A = πd

• A = πr

True or False: The diameter of a circle is always twice the length of its radius.

• False

• Depends on the circle

• True

What is the length of this circle's diameter?

Mathematical Equivalence

ON

Ethan, Luna, and Evelyn are planning a race around a circular garden. If the garden has a radius of 5 meters, how far will they have to run to complete one full lap around the garden?

• 10π meters

• 25π meters

• 20π meters

• 15π meters

A farmer has a circular fish pond with an area of 78.5 square meters. Can you find out its radius?

• 2.50 m

• 10.00 m

• 3.14 m

• 5.00 m

Zoe, Nora, and William are playing at the park. They come across a circular pond with a radius of 3.5 cm. They start wondering about the area of the pond. Can you help them figure it out?

• 7.07 cm

• 38.465 cm

• 12.25 cm

• 21.98 cm