Question

Medal and Fan
Not a multiple choice question, test, or Exam question
What is the formula for finding the height of a square pyramid who's volume is 8 cubic feet and a base length of 2 ft?

Answer 1

@vera_ewing @Voltage @Vocaloid

Answer 2

good, so we have

V = (1/3)(r^2)(h)

we have V and r, and we want to find h

Answer 3

yep:)

Answer 4

so we re-arrange our formula to get

h = 3V/(r^2)

now plug in V and r

Answer 5

I'm having a heard time isolating h

Answer 6

ok, want me to walk you through it?

Answer 7

Oh! wait!

Answer 8

nope, this formula works for a square pyramid

a cone would be (1/3)(pi)r^2h

Answer 9

if r = the side length of the base, that is

Answer 10

Alright, let's start again. I have 2 formulas for a square pyramid
\[\frac{ 1 }{ 6 } (b^3) \] and \[\frac{ 1 }{ 3 } (b) (h)\]

Answer 11

hm... the first formula only works if the height is equal to the side length of the base

Answer 12

lets use the second formula

V = (1/3)bh where b is the area of the base and h is the height

Answer 13

Okay so the formula would be \[\frac{ 1 }{ 3 } (2) (h)\]

Answer 14

oh, ok, if 2 is the area of the base, then yes

Answer 15

V = (1/3)(2h)

now multiply both sides by to "get rid of" the 1/3

Answer 16

base length rather :P

Answer 17

@Vocaloid

Answer 18

wait, why "cubic feet"? that implies 3 dimensions

Answer 19

if the side length is 2, then the base is 4

Answer 20

yeah, it's a square pyramid. like in my drawing

Answer 21

Ohh right! I forgot that BL= S^2

Answer 22

right, so if b = 4 then

V = (1/3)(4)(h)

know how to isolate h now?

Answer 23

Yeah I did it on my white board. Would it be h= \[\frac{ 1 }{ 3 } *8\frac{ 4 }\]

Answer 24

oh. O-o

Answer 25

nope, not quite

Answer 26

we want to "get rid of" the 1/3 fraction so we multiply both sides by 3

Answer 27

not like this?

Answer 28

V = (1/3)(4)(h)

3V = 4h

with me so far?

Answer 29

yes. So it would be V=8 right? because the vol is already given?

Answer 30

OH! it's 6?

Answer 31

nope, remember, we want to find h

Answer 32

3V = 4h

now divide both sides by 4

Answer 33

i though we need to divide 3V by 4 to isolate h?

Answer 34

right

Answer 35

h = 6, right

Answer 36

didn't see your answer up there ;P

Answer 37

Yeay! Thank you so much! I know I'm kinda slow but I love it when I can actually understand X)

Answer 38

i was seeing that V is substituted by 8