Circle Basics

Front

What is the definition of a circle?

Back

A circle is a set of points in a plane that are equidistant from a fixed point called the center.

Front

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is given by 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 given by the formula: A = πr², where r is the radius.

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 (d = 2r).

Front

If the radius of a circle is 5 cm, what is its diameter?

Back

The diameter is 10 cm.

Front

If the diameter of a circle is 14 cm, what is its radius?

Back

The radius is 7 cm.

Front

Calculate the circumference of a circle with a radius of 4 cm (use π = 3.14).

Back

C = 2πr = 2 × 3.14 × 4 = 25.12 cm.

Front

Calculate the area of a circle with a radius of 3 cm (use π = 3.14).

Back

A = πr² = 3.14 × (3)² = 28.26 cm².

Front

What is the relationship between radius, diameter, and circumference?

Back

The circumference is directly proportional to the diameter, and the diameter is twice the radius.

Front

What is the value of π (pi)?

Back

π (pi) is approximately equal to 3.14.