Explanation:
the area of a circle is
pi × r²
r being the radius = half of the diameter.
this pizza has 5 equal slices.
Bobby grabs 2 of the 5. that means 2/5 if the whole pizza.
the area of the whole pizza is
pi × (14/2)² = 49pi in²
2/5 of that is
49pi × 2/5 = 98pi/5 = 19.6pi in² = 61.57521601... in²