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 given distance from a fixed point, called the center.

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

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is calculated using the formula C = 2πr, where r is the radius.

Front

What is the formula for the area of a circle?

Back

The area (A) of a circle is calculated using the formula A = πr², where r is the radius.

Front

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

Back

The area is A = π(6)² = 36π ≈ 113.1 square inches.

Front

If a circle has a radius of 10 inches, what is its circumference?

Back

The circumference is C = 2π(10) = 20π ≈ 62.83 inches.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the radius (d = 2r).

Front

How do you convert radius to diameter?

Back

To convert radius to diameter, multiply the radius by 2.

Front

How do you convert diameter to radius?

Back

To convert diameter to radius, divide the diameter by 2.