Multiply both sides by 3 to get:
3r = sqrt(A)
Square both sides:
9r^2 = A
It can help because 9×4 =36, and 9×8=72. if you divide 72 by 2 you get 36 which is the answer to 9 ×4. basically because nine is the same in both problems you are multiplying by 4 (and you know 4 is half of 8) you can assume that multiplying the sum of 4 and 9 that you will get the sum of 8 and 9.
Answer: Option A
Take not that this is a square bulletin board thus area = Length Times Base. Notice how it says its a square as well? thus telling us that each side is of equal length
Squaring the value N would give us the value of the one side of the board
A rectangular prism is a cuboid so volume of cuboid is base area x height which is 5x5x12=300
volume of pyramid is 1/3 x base area x height = 5x5x6x1/3=50 thus volume outside pyramid and inside cuboid is 300-50=250
3/45 = 20/x...3 in to 45 seconds = 20 in to x seconds
cross multiply
(3)(x) = (45)(20)
3x = 900
x = 900/3
x = 300...300 seconds (or 5 minutes)to fill the tub with 20 inches
