Question

The diameter of a circle is 10 cm. Find its area in terms of π.

Answer 1

A = 25
`\pi`
`cm^(2)` or A = 78.54
`cm^(2)`

Explanation:

The diameter of a circle is just the radius two times, in this case, the diameter is 10. This means that the radius would be 5. Therefore we can use 5 as our r variable in the formula for area (A=
`\pi r^(2)`),

A =
`\pi 5^(2)`, simplify
`5^(2)`:

A = 25
`\pi`

From here you can leave the asnwer in its excat form, 25
`\pi`, or you can simplify it by multiply 25 times pi to get 78.54 (rounded to the hundreths place).

Answer 2

7.9577cm^2

Explanation:

10 = 2 * r * pi

==> r = 5/pi

area = r * r * pi = 25/pi = 7.9577cm^2