Area and Circumference of a Circle

Front

What is the definition of the radius of a circle?

Back

The radius of a circle is the distance from the center of the circle to any point on its circumference.

Front

What is the definition of the diameter of a circle?

Back

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

Front

How do you calculate the circumference of a circle?

Back

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

Front

What is the value of π (pi) approximately?

Back

π (pi) is approximately 3.14.

Front

If the radius of a circle is 7 cm, what is the circumference?

Back

Circumference = 2 × π × 7 cm ≈ 43.96 cm.

Front

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

Back

Radius = Diameter / 2 = 10 cm / 2 = 5 cm.

Front

What is the formula for the area of a circle?

Back

Area = π × radius².

Front

If the radius of a circle is 4 cm, what is the area?

Back

Area = π × (4 cm)² ≈ 50.24 cm².

Front

What is the relationship between diameter and radius?

Back

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

Front

How do you find the radius if you know the circumference?

Back

Radius = Circumference / (2 × π).