Radius and Diameter

Front

What is the radius of a circle?

Back

A line from the center of a circle to the edge.

Front

What is the diameter of a circle?

Back

A line across a circle through the center.

Front

If the diameter of a circle is 40 ft, what is the radius?

Back

20 ft

Front

If the diameter of a circle is 18 inches, what is the radius?

Back

9 inches

Front

If the diameter of a circle is 156 inches, what is the radius?

Back

78 inches

Front

How do you find the radius from the diameter?

Back

Divide the diameter by 2.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the radius.

Front

If the radius of a circle is 5 cm, what is the diameter?

Back

10 cm

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × radius.

Front

What is the formula for the area of a circle?

Back

Area = π × radius².