volume = π x r^2 x h
diameter = 20, radius = 20/2 = 10
10^2 = 100
100 * 5 = 500
volume = 500π cubic cm
Answer:
3/8 of 24 is 9
9 of her pencils are sharpened.
Answer:
The sheet should be turned up 7.5cm on each side to obtain maximum volume.
Step-by-step explanation:
If we make a rectangular eavesdrop, by bending the sheet along dotted line, then.
Height of eaves trough = x cm
Length of eaves trough = 600 cm
Width of eaves trough = (30 - 2x) cm
We know that Volume is given by:
V = Length · Width · Height
V = (x)(30 - 2x)(600)
V = -1200x² + 18000x
To maximize the volume, we take the derivative and put it equal to zero.

First we need to find delta for function ax2+bx+c = 0
DELTA = b2-4ac
DELTA = 25 -( 4*1*5)= 25 - 20 = 5
x1 = (-b-√DELTA)/2a = (-5 - √5)/2
x2 = (-b+√DELTA)/2a (-5+√5)/2
x1 and x2 are zeros of this function