63[tex] \pi [/tex]
The sector is [tex] \frac{70}{360} [/tex]; there are 360 degrees in a circle.
You use the formula [tex] \pi r^{2} [/tex].
18cm is the radius, and then you square it to get 324.
Multiply 324 by [tex] \frac{70}{360} [/tex]
You get 63[tex] \pi [/tex]
