Area and Circumference of a Circle Review

Front

What is the formula for the area of a circle?

Back

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

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Front

If the radius of a circle is 15 cm, what is the area?

Back

A = π(15)² = 706.5 cm².

Front

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

Back

C = 2π(5) = 31.4 inches.

Front

What is the relationship between diameter and radius?

Back

Diameter (d) = 2 × Radius (r).

Front

What is the diameter of a circle with a radius of 3.5 cm?

Back

Diameter = 2 × 3.5 cm = 7 cm.

Front

What do you need to calculate to find out how much fencing is required for a circular playground?

Back

You need to calculate the circumference.

Front

What is the area of a circle with a radius of 5 m?

Back

A = π(5)² = 78.5 m².

Front

What is π (Pi)?

Back

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

Front

How do you convert radius to diameter?

Back

Multiply the radius by 2.