Intro to Circles

If my radius is 10ft, what is my diameter?

• 20ft
• 5ft
• 31.4ft
• 62.8ft

If my diameter is 19 inches, what is my radius?

• 38 inches
• 9.5 inches
• 59.66 inches
• 119.32 inches

What is the formula for finding the circumference of a circle?

• C = r²

• C = rd

• A = π·r²

• C = π·d

What is the diameter of a circle?

• the distance around a circle

• the area of a circle

• halfway through a circle

• a line through the center of a circle

What is the circumference of a circle?

• the distance around a circle

• the area of a circle

• halfway through a circle

• a line through the center of a circle

The Jones family wants to enclose their circular garden with a fence. To the nearest foot, what is the minimum length of fencing they need to buy?

• 56.25 ft
• 246 ft
• 365 ft
• 393 ft

A DVD has a diameter of 15 millimeters. What is the circumference?

• c = 15π
• C = 2π15
• c = 15/π
• c = 15/2π

Daniel bought a cookie at lunch. The radius of a cookie is 5 inches. What is the cookie’s circumference?

• ≈10 in
• ≈2.5 in
• ≈15.7 in
• ≈31.4 in 

Mrs. Apple just bought a new dinning room table. She needs to make a table cloth for decoration. What amount of fabric should she buy if the table has a diameter of 5 feet? Choose the equation that would best help solve this problem.

• C = π5
• C = (2)(π)(2.5)
• A = π5²
• A = π2.5²

The circumference of a pizza is 35 inches. What is the approximate  radius of the pizza?

• 11 inches
• 5.6 inches
• 17.5 inches
• 3.5 inches