Calculating the Area of a Circle

This video tutorial explains how to calculate the area of a circle using three different methods: the radius, the diameter, and the circumference. It provides step-by-step instructions and examples for each method. Using the radius, the formula is area = πr². For the diameter, the diameter is halved to find the radius, then the same formula is applied. Using the circumference, the formula is area = c² / (4π). Each method is demonstrated with a practical example to ensure understanding.

What is the formula to calculate the area of a circle using its radius?

• Area = 2 * pi * r

• Area = pi * r squared

• Area = pi * r

• Area = pi * diameter

If the radius of a circle is 6 inches, what is the area?

• 226.08 square inches

• 72 square inches

• 36 square inches

• 113.04 square inches

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

• Divide the diameter by 2

• Multiply the diameter by 2

• Square the diameter

• Multiply the diameter by pi

Using a diameter of 20 inches, what is the radius?

• 40 inches

• 20 inches

• 5 inches

• 10 inches

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

• 314.16 square inches

• 200 square inches

• 100 square inches

• 628.32 square inches

What formula is used to find the area of a circle using its circumference?

• Area = c squared over 4 pi

• Area = 2 * pi * c

• Area = c over 2 pi

• Area = pi * c squared

If the circumference of a circle is 42 inches, what is the area?

• 140.4 square inches

• 1764 square inches

• 84 square inches

• 264.6 square inches

What is the result of squaring the circumference (42 inches) in the area calculation?

• 84

• 21

• 1764

• 882

How do you calculate the area from the squared circumference value?

• Multiply by pi

• Divide by 4 pi

• Multiply by 2 pi

• Divide by 2 pi