Answer:
The radius of the cone is 9cm
Step-by-step explanation:
This problem bothers on the mensuration of solid shapes, a cone
The volume of a cone is expressed as
V=1/3(πr²h)
We were told that the radius r and the height h are equal
I.e r=h
Substituting h=r in the formula we have
V= 1/3(πr²*r)
V =1/3(πr³)
To find the radius r let us substitute our given 763.02cm³ (note we assume unit in cm)
763.02= 1/3(3.142r³)
763.02= (3.142r³)/3
763.02*3=3.142r³
2289.06=3.142r³
r³=2289.06/3.142
r³= 728.54
r= ³√728.54
r= 8.99cm
≈r= 9cm
Answer: 30:5
Step-by-step explanation:
Five levels were beaten so thirty levels are left so whats left to what’s beaten is 30:5
We can create two equations here:
(1) Volume = area of square * height of box
85.75 = s^2 h
(2) Cost = 3 * area of square + 1.5 * area of side box
C = 3 s^2 + 1.5 s h
From (1), we get:
h = 85.75 / s^2
Combining this with (2):
C = 3 s^2 + 1.5 s (85.75 / s^2)
C = 3 s^2 + 128.625 s-
Taking the 1st derivative and equating dC/ds =
0:
dC/ds = 6s – 128.625 / s^2 = 0
Multiply all by s^2:
6s^3 – 128.625 = 0
6s^3 = 128.625
s = 2.78 cm
So h is:
h = 85.75 / s^2 = 85.75 / (2.78)^2
h = 11.10 cm
So the dimensions are 2.78 cm x 2.78 cm x 11.10 cm
The total cost now is:
C = 3 (2.78)^2 + 1.5 (2.78) (11.10)
C = $69.47
