3/25 - Circumference & Area of Circles Review

What is the diameter?

• 5 in
• 10 in
• 3.14 in
• 15.84 in

What is the formula for area of a circle?

• A = π⋅r²
  
• A = d⋅π
• A = 2⋅π⋅r
• A = 2⋅r

What is the formula for circumference of a circle?

• C = d⋅π
• C = 2⋅π⋅r
• C = π⋅r²
• C = d⋅π and
  C = 2⋅π⋅r

A circle's diameter is 13 cm.  What is the approximate circumference?  

• 6.5 cm
• 13 cm
• 40.8 cm 
• 20.4 cm 

Mrs. Wilson placed the welcome mat shown below on her front door step. What is the area of her welcome mat in square feet? Leave in terms of π.

• A = 2π
• A = 8π
• A = 10π
• A = 4π

The diameter of the face-off circle on an ice-hockey rink is 30 feet. Find its area.

• 675.6 ft²
• 29.67 ft²
• 545.8 ft²
• 706.5 ft²

If you are given the diameter, how can you calculate the radius?

• Multiply the diameter by 2
• Divide the diameter by 2
• Add 2 to the diameter
• Subtract 2 from the diameter

Mrs. Whaley 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 = π x 5 x 5

• A = π x 2.5 x 2.5

What is the area of this circle?

• 82.13 m²
• 78.50 m²
• 314.16 m²
• 170.12 m²

A DVD has a diameter of 15 millimeters. Which equation would help you determine the distance around the DVD?

• C = 15π

• A = π7.5²

• A = 15 ÷ π

• C = 7.5π