7th Grade Circumference and Area Test

Front

What is the formula for the circumference of a circle?

Back

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

Front

If the radius of a circle is 8 inches, what is the circumference?

Back

50.24 inches.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × radius.

Front

If a circle has a circumference of 25.12 inches, what is its diameter?

Back

8 inches.

Front

What is the formula for the area of a circle?

Back

Area = π × radius².

Front

If the area of a circle is 200.96 in², what is its circumference?

Back

50.24 inches.

Front

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

Back

Radius = Circumference / (2 × π).

Front

What is the diameter of a circle with a radius of 9 inches?

Back

18 inches.

Front

If a circular swimming pool has a diameter of 21 feet, how do you find the circumference?

Back

Circumference = π × diameter = π × 21 ft.

Front

What is the circumference of a circle with a diameter of 10 feet?

Back

31.42 feet.