Circles - diameter and radius

Front

What is the radius of a circle?

Back

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

Front

What is the diameter of a circle?

Back

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

Front

If the radius of a circle is 9, what is the diameter?

Back

The diameter is 18 (Diameter = 2 x Radius).

Front

If the diameter of a circle is 14, what is the radius?

Back

The radius is 7 (Radius = Diameter / 2).

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the length of the radius.

Front

If the radius of a circle is 13, what is the diameter?

Back

The diameter is 26 (Diameter = 2 x Radius).

Front

If the radius of a circle is 25, what is the diameter?

Back

The diameter is 50 (Diameter = 2 x Radius).

Front

If the diameter of a circle is 34, what is the radius?

Back

The radius is 17 (Radius = Diameter / 2).

Front

What is the formula for the circumference of a circle?

Back

Circumference = π x Diameter or Circumference = 2 x π x Radius.

Front

What is the area of a circle?

Back

Area = π x (Radius)^2.