Area of Circles

Front

What is the formula for the area of a circle?

Back

A = π × r²

Front

What does 'radius' mean in relation to a circle?

Back

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

Front

What is the diameter of a circle?

Back

The diameter is twice the length of the radius and is the distance across the circle through its center.

Front

How do you calculate the area of a circle if you know the diameter?

Back

First, divide the diameter by 2 to get the radius, then use the formula A = π × r².

Front

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

Back

A = π × (5 cm)² = 78.5 cm² (approximately).

Front

What is the relationship between diameter and radius?

Back

The diameter is equal to 2 times the radius (D = 2r).

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, used in calculations involving circles.

Front

If a circle has an area of 50.24 cm², what is its radius?

Back

To find the radius, use the formula r = √(A/π). For A = 50.24 cm², r ≈ 4 cm.

Front

What is the area of a circle with a radius of 4.5 feet?

Back

A = π × (4.5 ft)² ≈ 63.585 ft².

Front

How do you convert diameter to radius?

Back

To convert diameter to radius, divide the diameter by 2.