Circumference and Area

Circumference and Area

Multiple Choice

If the diameter is 48m, what is the radius?

• 96m

• 24m

• 12m

• 4m

Multiple Choice

If the radius is 34in, what is the diameter?

• 17in

• 68in

• 3.4in

• 22in

Circumference is...

C = d π or diameter times pi

C = 2 π r or radius times 2 times pi

π is 3.14

Multiple Choice

Which measurement of a circle do you need to find the CIRCUMFERENCE?

• Diameter

• Radius

Multiple Choice

What is the circumference of the circle shown?

• 113.04 because you multiply 36 and π

• 56.52 because you multiply 18 and π

Multiple Choice

A circle has a RADIUS of 15 cm. What is the CIRCUMFERENCE of this circle?

• 47.1 cm because you multiply 15 and π

• 94.2 cm because you multiply 30 and π

Multiple Choice

A circle has a DIAMETER of 20m. What is the circumference of this circle?

• 31.4m

• 62.8m

Area

remember to use the radius in finding area. If you are given a DIAMETER, divide it by 2.

To square the radius we multiply it to itself.

Example: 9² = 9x9 = 81

Multiple Choice

What measurement of a circle do you need to find the AREA?

• Diameter

• Radius

Multiple Choice

If a circle has a radius of 5, what is the Area of the circle?

• 15.7

• 78.5

Multiple Choice

What is the area of the circle shown?

• 113.04

• 452.16

Multiple Choice

What is the AREA of a circle with a radius of 7cm?

• 21.98cm

• 153.86cm

• 43.96cm