Here we have to use the formula of area of sector, which is
[tex] A = (\frac{\Theta}{360})*\pi r^2 [/tex]
Theta = 70 degree, and radius is unknown here. It is given that area = 7 pi .
Substituting the given values in the formula, we will get
[tex] 7 \pi = (\frac{70}{360})*\pi r^2 [/tex]
[tex] \frac{7 \pi * 360}{70 \pi}=r^2 [/tex]
[tex] 36 = r^2=>r=6ft [/tex]
Therefore the correct option is the first option .
