Answer:
n = 100
Step-by-step explanation:
the area (A) of the sector is calculated as
A = area of circle × fraction of circle
given A = 40π , then
πr² × [tex]\frac{n}{360}[/tex] = 40π
π × 12² × [tex]\frac{n}{360}[/tex] = 40π
144π × [tex]\frac{n}{360}[/tex] = 40π ( divide both sides by π )
144 × [tex]\frac{n}{360}[/tex] = 40 ( multiply both sides by 360 to clear the fraction )
144n = 14400 ( divide both sides by 144 )
n = 100
