Circles Review Circumference and Area

Mod.8 Circles Review

Circumference and Area

​Warm Up:

What two formulas can be used to find the circumference of a circle?

​WE do:

The circumference of a circular garden is 106.76 feet. What is the diameter of the garden? Use 3.14 for π and do not round your answer.

​WE do:

The circumference of a circular garden is 106.76 feet. What is the diameter of the garden? Use 3.14 for π and do not round your answer.

Math Response

The circumference of a circular garden is 12.56 feet. What is the diameter of the garden? Use 3.14 for π and do not round your answer.

Type answer here

Correct Answer: 4

Deg^°

Rad

​We do:

Find the circumference of a circle with a diameter of 5 yds. Use 3.14 for π. Do not round your answer.

​We do:

Find the circumference of a circle with a diameter of 5 yds. Use 3.14 for π. Do not round your answer.

Multiple Choice

Find the circumference a circle with a diameter of 12 cm. Use 3.14 for π. Round your answer to the nearest hundredth.

• 18.84 cm

• 75.36 cm

• 37.68 cm

​We do:

Find the area of a circle with a diameter of 5 yds.

Use 3.14 for π. Do not round your answer.

​We do:

Find the area of a circle with a diameter of 5 yds.

Use 3.14 for π. Do not round your answer.

Multiple Choice

Find the area of the circle, giving your answer to 1 decimal place.

• 3.1 cm²

• 12.6 cm²

• 6.3 cm²

• 50.3 cm²

​We do:

Find the area of a circle with a radius of 5 m. Write your answers in terms of π. Do not round your answer and be sure to include the correct units in your answers.

​We do:

Find the area of a circle with a radius of 5 m. Write your answers in terms of π. Do not round your answer and be sure to include the correct units in your answers.

Math Response

Find the area of a circle with a radius of 8 cm. Write your answers in terms of π.

Do not round your answer.

Type answer here

Correct Answer: 64\pi

Deg^°

Rad

Multiple Choice

Is the red line a radius or diameter of the circle?

• Radius

• Diameter

Math Response

Jayne has a very large circular lollipop that has a circumference of 25.12 inches. What would the diameter of Jayne’s lollipop be? Use π = 3.14.

Type answer here

Correct Answer: 8

Deg^°

Rad

Math Response

What is the area of this circle?

Use 3.14 for π.

Type answer here

Correct Answer: 1133.54

Deg^°

Rad

Multiple Choice

What does area mean?

• the distance around a shape
• half the distance around a shape
• the amount of space outside a shape
• the amount of space inside a shape

Multiple Choice

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

Multiple Select

Select all of the formulas below that can be used to find the circumference of a circle.

• πd

• πr²

• πdr

• 2rπd

• 2πr

Multiple Choice

If the radius is 5, which formula represents the area of a circle?

$$A=\pi r^2$$  

• $$A=\pi5^2$$  

• $$A=\pi10^2$$  

Math Response

Find the circumference of the circle.

Type answer here

Correct Answer: 15.7

Deg^°

Rad

Multiple Choice

The radius of the circle is 9 meters.  What is the circle's circumference?

• 9 meters
• 28.26 meters
• 56.52 meters
• 18 meters

Math Response

Mrs. Wilson placed the welcome mat shown below on her front door step.

What is the area of her welcome mat in square feet? Round to the nearest hundredth.

____sq. inches

Type answer here

Correct Answer: 25.12

Deg^°

Rad

Math Response

A glass stained window is shaped like a semicircle. The bottom edge of the window is 36 inches long.

How much colored glass would you need to cover the stained window? Round to the nearest hundredth.

Type answer here

Correct Answer: 508.68

Deg^°

Rad