Area and circumference of Circles

Front

What is the formula for the circumference of a circle?

Back

C = πd or C = 2πr, where C is circumference, d is diameter, and r is radius.

Front

What is the formula for the area of a circle?

Back

A = πr², where A is area and r is radius.

Front

What is the diameter of a circle?

Back

The measurement from one edge of the circle to the opposite edge, passing through the center.

Front

What is the radius of a circle?

Back

The measurement from the center of a circle to an edge of the circle.

Front

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

Back

10 inches (Diameter = 2 * Radius).

Front

If the diameter of a circle is 12 feet, what is the radius?

Back

6 feet (Radius = Diameter / 2).

Front

What is π (pi)?

Back

The ratio of the circumference of any circle to its diameter, approximately equal to 3.14.

Front

How do you calculate the circumference of a circle with a radius of 7 cm?

Back

C = 2πr = 2 * 3.14 * 7 = 43.96 cm.

Front

How do you calculate the area of a circle with a diameter of 10 m?

Back

A = πr² = π(5)² = 25π ≈ 78.54 m².

Front

What is the relationship between diameter and radius?

Back

Diameter is twice the radius (Diameter = 2 * Radius).