Help ...The height of a square pyramid is 5 meters shorter than the side of its base. Its volume is 108 cubic meters, how tall is the pyramid

V= (1/3)BH
B= b^2
H=b-5

108= (1/3)(b-5)(b^2)
b^3-5b^2 -324=0

Question

Help ...The height of a square pyramid is 5 meters shorter than the side of its base. Its volume is 108 cubic meters, how tall is the pyramid 

V= (1/3)BH
B= b^2
H=b-5

108= (1/3)(b-5)(b^2)
b^3-5b^2 -324=0

mayankdevnani · Answer

let the height of square pyramid be `h`,
So,base of square pyramid will be `5+h`

mayankdevnani · Answer

$$\large \bf VOLUME=a^2\times \frac{h}{3}$$
$$\large \bf a=base~and~h=height$$

mayankdevnani · Answer

plug the values,we get
$$\large \bf 108=(5+h)^2 \times \frac{h}{3}$$

mayankdevnani · Answer

and solve for `h`?

anonymous · Answer

@mayankdevnani  i will get a cubic right ? wont that give me more than one value for h?

mayankdevnani · Answer

yeah !! i think two of them would be -ve or imaginary !

mayankdevnani · Answer

solve it and then tell me

anonymous · Answer

okay thank you @mayankdevnani

mayankdevnani · Answer

your welcome :)