Question

help!?!?
Find the length of the base of a square pyramid if the volume is 128 cubic inches and has a height of 6 inches. Use 3.14 for pi and round your answer to the nearest hundredth.

4 inches

8 inches

16 inches

24 inches

Answer 1

Volume of a rectangular prism (or box) is:
V = lwh {length x width x height}

8(x - 7)(x - 7) = 648
(x - 7)(x - 7) = 81
x² - 14x + 49 = 81
x² - 14x - 32 = 0
(x - 16)(x + 2) = 0
x - 16 = 0 or x + 2 = 0
x = 16 or x = -2
x = 16 x cannot be negative for x - 7 being the width and length

the value of x is 16

Answer 2

where did the prism come from :O

Answer 3

Volume prism = 1/3 * base area * height

Answer 4

oh ya....i just realized its not a prism.....thn idk what to do here

Answer 5

opppss.. i mean pyramid lol

Answer 6

1/3 * x^2 * 6 = 128
solve for x (x is the base of that pyramid)

Answer 7

yeah, no pi here. because the base is a square not a circle

Answer 8

how to find x by the way (finding the x was the reason i failed geometry )

Answer 9

1/3 * x^2 * 6 = 128

see 1/3 * 6 = 2
so, we get
2 x^2 = 128
divided by 2 on both sides, get
2x^2/2 = 128/2
x^2 = 64
x = sqrt(64) = ... ?

Answer 10

8

Answer 11

yup, x = 8

Answer 12

so the answer is 8 inches

Answer 13

that's right!

Answer 14

thx could u help me to solve another question??

Answer 15

okay, close this and post it in the new question

Answer 16

welcome :)