Area and Circumference of Circles

Front

What is the definition of a circle?

Back

A circle is a shape consisting of all points in a plane that are a fixed distance (radius) from a center point.

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 twice the length of the radius and is the distance across the circle through the center.

Front

How do you calculate the circumference of a circle?

Back

Circumference = 2 × π × radius or Circumference = π × diameter.

Front

What is the value of π (pi)?

Back

π (pi) is approximately 3.14 or 22/7.

Front

What is the formula for the area of a circle?

Back

Area = π × radius².

Front

If a circle has a radius of 6 inches, what is its area?

Back

Area = π × (6)² = 113.1 square inches.

Front

If a circle has a diameter of 12 inches, what is its radius?

Back

Radius = Diameter / 2 = 12 / 2 = 6 inches.

Front

What is the circumference of a circle with a radius of 6 inches?

Back

Circumference = 2 × π × 6 = 37.68 inches.

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the length of the radius.