Area of Circles

Front

What is the formula to calculate the area of a circle?

Back

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

Front

If a circle has a radius of 3 cm, what is its area?

Back

Using the formula A = πr², the area is A = π(3)² = 28.27 cm² (approximately).

Front

What is the relationship between diameter and radius in a circle?

Back

The diameter is twice the length of the radius. Therefore, d = 2r.

Front

How do you convert diameter to radius?

Back

To convert diameter to radius, divide the diameter by 2. r = d/2.

Front

What is the area of a circle with a diameter of 10 inches?

Back

First, find the radius: r = 10/2 = 5 inches. Then, A = π(5)² = 78.54 in² (approximately).

Front

What is the area of a circle with a radius of 4 meters?

Back

Using the formula A = πr², the area is A = π(4)² = 50.27 m² (approximately).

Front

What is the significance of π (pi) in circle calculations?

Back

π (pi) is a constant approximately equal to 3.14159, used in formulas related to circles, including area and circumference.

Front

How do you find the area of a circular window with a diameter of 12 meters?

Back

First, find the radius: r = 12/2 = 6 meters. Then, A = π(6)² = 113.10 m² (approximately).

Front

What is the area of a circle with a radius of 2.75 cm?

Back

Using the formula A = πr², the area is A = π(2.75)² = 23.75 cm² (approximately).

Front

If a clock face has a diameter of 19 inches, what is its area?

Back

First, find the radius: r = 19/2 = 9.5 inches. Then, A = π(9.5)² = 283.53 in² (approximately).