Since 90 degree is 1/4 of a circle, the area will be 1/4 th area of the full circle.
The radius is given by, r = 8 ft, therefore, the area of the full circle is,

Therefore, the area of the sector is,

Answer:
PB = 1.8
Step-by-step explanation:
PQ = 8 cm, BC = 10 cm and AB = 9 cm
∆ABC is similar to ∆APQ.
Therefore:

Plug in the values

Cross multiply
AP × 10 = 8 × 9
AP × 10 = 72
Divide both sides by 10
AP = 7.2
PB = AB - AP
PB = 9 - 7.2
PB = 1.8
Well supposing that you want all fish gone -
The answer would be 8
56 (divided) 7 = 8
Day 1 - 48
Day 2 - 40
Day 3 - 32
Day 4 - 24
Day 5 - 16
Day 6 - 8
Day 7 - 0
Hope this was what you were looking for :)