Circle Parts and Circumference

Front

What is the symbol for pi?

Back

π (pi) is a mathematical constant approximately equal to 3.14.

Front

What is the formula to calculate the circumference of a circle?

Back

Circumference = 2 × π × radius or Circumference = π × diameter.

Front

What is the distance around the outside of the circle called?

Back

Circumference.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

Front

What is a radius?

Back

A radius is a line segment from the center of the circle to any point on its circumference.

Front

What is a chord in a circle?

Back

A chord is a line segment whose endpoints lie on the circle.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius (Diameter = 2 × Radius).

Front

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

Back

Circumference = 2 × π × 5 cm ≈ 31.4 cm.

Front

What is the area of a circle?

Back

Area = π × radius².

Front

What is the term for the longest chord in a circle?

Back

The diameter.