What is the area of the following circle?

the diameter is 10.

Answer: 78.5 units²

Step-by-step explanation: To find the area of a circle, start with the formula for the area of a circle.

Area = πr²

Notice that here, we're given the diameter instead of the radius. It's important to understand that the radius is equal to half of the diameter so the radius of this circle will be equal to half of 10 or 5.

So plugging into the formula, we have (π) (5) ².

A common mistake is to plug 10 into the formula but remember that we must plug in the radius and not the diameter.

Multiplying, (5) ² is equal to 5 x 5 or 25 so we have 25π.

So the area of the circle is 25π.

Now, remember that π is approximately equal to 22/7 or 3.14 so we can estimate the area of the circle by plugging in 3.14 for π.

So we have (25) (3.14) which is equal to 78.5 units².

Since there were no labels, I just add units to the end.

So the area of the circle is approximately equal to 78.5 units².

Answer: The area of the circle with a diameter of 10 cm is 78.5 cm2.