Circles

Front

What is a circle?

Back

A circle is a shape consisting of all points in a plane that are a fixed distance 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 the distance across the circle through the center, equal to twice the radius.

Front

How do you calculate the circumference of a circle?

Back

Circumference can be calculated using the formula C = 2πr, where r is the radius.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the length of the radius (D = 2r).

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

If the radius of a circle is 10 in, what is the diameter?

Back

The diameter is 20 in.

Front

If the diameter of a circle is 16, what is the radius?

Back

The radius is 8.

Front

What is the formula for the area of a circle?

Back

The area can be calculated using the formula A = πr².

Front

If the radius of a circle is 18, what is the area?

Back

The area is approximately 1017.88 square units.