Area and Circumference

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Front

How do you calculate the radius from the circumference?

Back

Radius can be calculated using the formula r = C / (2π).

Front

What is the relationship between diameter and radius?

Back

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

Front

What is the formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

Front

How do you calculate the diameter from the circumference?

Back

Diameter can be calculated using the formula d = C / π.

Front

What is the value of π (pi) approximately?

Back

π is approximately 3.14.

Front

If the radius of a circle is 5 inches, what is the circumference?

Back

C = 2π(5) = 31.4 inches.

Front

If the diameter of a circle is 10 cm, what is the area?

Back

A = π(5)² = 78.5 cm².

Front

What is the circumference of a circle with a radius of 10 inches?

Back

C = 2π(10) = 62.8 inches.

Front

What is the area of a circle with a diameter of 8 cm?

Back

A = π(4)² = 50.24 cm².