Area of a Circle

Front

What is the formula for calculating the area of a circle?

Back

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

Front

If the diameter of a circle is 18 cm, what is the radius?

Back

The radius is half of the diameter. Therefore, if the diameter is 18 cm, the radius is 9 cm.

Front

How do you convert diameter to radius?

Back

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

Front

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

Back

Using the formula A = πr², the area is approximately 63.585 ft².

Front

What is the area of a circle with a diameter of 13 feet?

Back

First, find the radius (13 ft / 2 = 6.5 ft). Then, use the formula A = πr² to find the area, which is approximately 133 ft².

Front

What is the value of π (pi) used in area calculations?

Back

The value of π (pi) is approximately 3.14 or can be used as 22/7 for calculations.

Front

How do you round a number to the nearest whole number?

Back

To round a number to the nearest whole number, look at the digit to the right of the decimal point. If it is 5 or greater, round up; if it is less than 5, round down.

Front

What is the area of a circle with a diameter of 8 meters?

Back

The radius is 4 meters (8 m / 2). The area is approximately 50.27 m² using the formula A = πr².

Front

What is the significance of the radius in calculating the area of a circle?

Back

The radius is crucial because it is the measurement used in the area formula A = πr². It determines the size of the circle.

Front

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

Back

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