WHYS.video

How to Calculate the Area of a Circle with an 18 cm Diameter

Discover the step-by-step method to find the area of an 18 cm diameter circle using the formula A = πr².

Published

Video transcript

To find the area of a circle with an 18 cm diameter, use the formula A = πr^2. First, find the radius by dividing the diameter by 2, giving 9 cm. Then calculate the area: A = π × (9 cm)^2 ≈ 254.47 cm².

Questions and answers

  1. What is the formula for the area of a circle?

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

  2. How do you find the radius of a circle from its diameter?

    To find the radius, divide the diameter by 2.

  3. What is the area of a circle with a radius of 10 cm?

    The area would be approximately 314.16 cm², calculated using A = π(10 cm)².

  4. Can you calculate the area of circles quickly?

    Yes, by memorizing the formula A = πr², you can quickly calculate areas of circles once you know the radius.

Related questions

Continue exploring

For more math tutorials on geometry or to enhance your understanding of circle properties, check out our other videos on circle equations and area calculations.