Question

What is the area of a circle

Answer 1

To solve for the area of a circle, use the formula, π r ^2, where r = radius of the circle.

Identify the radius of the circle, and multiply it by itself (or square it). Multiply the number to Pi (which is 3.14) and you will get the area of a circle.

If only given a diameter, multiply it by one-half (or simply get the diameter's half). Then, continue with the formula.

Example:

Assuming that in a circle, the given diameter is 12 cm, therefore when you get its half, the radius is 6 cm. Square it or multiply it by itself, and you'll get 36 cm.

Note: {You have to square it first before multiplying it to Pi because of the rule in PEMDAS wherein EXPONENTS come before MULTIPLICATION. "r^2" is followed first in the area of a circle rule.}

And lastly, multiply 3.14 and 36 which will give you the answer of 113.04 cm^2 (Any unit that is given will always be squared in the final answer).

You can write the answer as either 36π cm^2 or 113.04 cm^2

Answer 2

Hi there!


`\textbf\red{\pi r^2}`


`\textbf{EXPLANATION}` :-


`\int^(r)_(0) \:2πr \:dr = 2π\: \int^(r)_(0) \:r\: dr`

⇒
`2π \int^(r)_(0) \: (r^2)/(2)`

⇒
`2π (r^2)/(2) - 2π (0^2)/(2)`

⇒
`\frac{2π{r}^2}{2}`

⇒
`\textbf\red{\pi r^2}`

~ Hope it helps!