Radius and Diameter

Front

What is the definition of radius?

Back

The radius is the distance from the center of a circle to any point on its circumference.

Front

What is the definition of diameter?

Back

The diameter is the distance across a circle through its center, equal to twice the radius.

Front

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

Back

10 cm

Front

If the diameter of a circle is 12 m, what is the radius?

Back

6 m

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the radius.

Front

How do you calculate the circumference of a circle using the radius?

Back

Circumference = 2 × π × radius.

Front

How do you calculate the area of a circle using the radius?

Back

Area = π × radius².

Front

If the radius of a circle is 3 yd, what is the circumference?

Back

Approximately 18.85 yd.

Front

If the diameter of a circle is 20 in, what is the radius?

Back

10 in.

Front

What is the formula for finding the radius if you know the circumference?

Back

Radius = Circumference / (2 × π).