Circles: Area vs Circumference

Front

What is the formula for the circumference of a circle?

Back

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

Front

How do you calculate the area of a circle?

Back

A = πr², where r is the radius.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius (d = 2r).

Front

If a circle has a radius of 5 cm, what is its diameter?

Back

The diameter is 10 cm.

Front

What is the circumference of a circle with a diameter of 20 cm?

Back

C = 20π cm or approximately 62.83 cm.

Front

What is the radius of a circle with a circumference of 31.4 cm?

Back

The radius is 5 cm.

Front

What does the term 'circumference' refer to?

Back

Circumference is the distance around the circle.

Front

What is the area of a circle with a radius of 3 m?

Back

A = π(3)² = 28.27 m² (approximately).

Front

How do you convert diameter to radius?

Back

Divide the diameter by 2.

Front

What is the circumference of a circle with a radius of 10 mm?

Back

C = 2π(10) = 20π mm or approximately 62.83 mm.