Area and Circumference of a Circle

Front

What is the definition of a radius in a circle?

Back

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

Front

What is the definition of a diameter in a circle?

Back

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

Front

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

Back

10 inches

Front

What is the formula for calculating the circumference of a circle?

Back

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

Front

If the diameter of a circle is 12 inches, what is the circumference?

Back

Approximately 37.68 inches (using π ≈ 3.14).

Front

What is the formula for calculating the area of a circle?

Back

Area = π × radius².

Front

If the radius of a circle is 3 inches, what is the area?

Back

Approximately 28.26 square inches (using π ≈ 3.14).

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the length of the radius.

Front

If the circumference of a circle is 31.4 inches, what is the radius?

Back

Approximately 5 inches (using the formula Circumference = 2 × π × radius).

Front

What is the value of π (pi) approximately?

Back

Approximately 3.14.