Area and Circumference of Circles Practice

Front

What is the area of a circle?

Back

The area of a circle is calculated using the formula A = πr², where r is the radius.

Front

What is the circumference of a circle?

Back

The circumference of a circle is calculated using the formula C = πd or C = 2πr, where d is the diameter and r is the radius.

Front

What is the radius of a circle?

Back

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

Front

What is the diameter of 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 7 cm, what is the area?

Back

A = π(7 cm)² = 49π cm² (approximately 153.94 cm²).

Front

If the diameter of a circle is 10 m, what is the circumference?

Back

C = πd = π(10 m) = 10π m (approximately 31.42 m).

Front

What do you need to find the circumference of a circle?

Back

You need the diameter or the radius of the circle.

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

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

Back

The radius is half of the diameter. r = d/2.

Front

What is the formula to find the area of a circle if you know the diameter?

Back

A = π(d/2)² = (π/4)d².