Circle Formulas and Problems

Front

What is the formula for Circumference?

Back

C = 2πr

Front

What is the formula for Diameter?

Back

d = 2r

Front

What is the formula for Area?

Back

A = πr^2

Front

What is the formula for Radius?

Back

r = \frac{d}{2}

Front

What is the relationship between Diameter and Radius?

Back

Diameter is twice the Radius (d = 2r).

Front

How do you calculate the Circumference of a circle with a radius of 5 units?

Back

C = 2π(5) = 10π ≈ 31.42 units.

Front

If the Diameter of a circle is 10 units, what is the Radius?

Back

r = \frac{10}{2} = 5 units.

Front

What is the Area of a circle with a Radius of 3 units?

Back

A = π(3^2) = 9π ≈ 28.27 square units.

Front

If the Circumference of a circle is 62.83 units, what is the Radius?

Back

r = \frac{C}{2π} = \frac{62.83}{2π} ≈ 10 units.

Front

What is the formula to convert Radius to Diameter?

Back

d = 2r.