Algebra 2 help?

Question

Can anyone explain to me how you get h=2/pi if you are solving for h in the problem....

V=(pi)(r-squared)(h) ; V=128, r=8

Thanks in advance...

Answer 1

128 = (pi)(8^2)h make substitutions
128 = 64(pi)h square 8
2 = (pi)h divide each side by 64
2/(pi) = h divide each side by (pi)

As this is an algebra problem, do not substitute aproximations for irrational numbers like Pi or e like the others are doing... You don't need a calculator nor will you be allowed to use one on the test.

Answer 2

It simple!! All you have to do is keep the formula written the same way and just plug in the numbers for what is given.

V=128, r=8

128=(pi)(8)2(h)
everyone knows that pi= 3.14 so plug that in too.
128=3.14(8)2(h)
then solve and multiply on each side only
128= 3.14(64)(h)
i got 64 because 8 times 8 is 64 not 8 times 2. You solve exsponents first. now multiply the only number you have to multiply.
128=200.96(h)
Now, all you have to do is solve for h. So you want the equation to say (h=) so you need to move 200.96 to the other side. You do this by dividing 200.96 to both sides. 200.96/200.96 gives you 1.
128/200.96=1h
now solve the problem on the remaining side
.6369=h
there is your answer

Answer 3

Just plug in the number you already know!

V = 128
r = 8
pi = 3.14159

The equation is V = (pi) * (r ^ 2) * (h)
128 = (3.14159) * (8 ^ 2) * (h)
128 = (3.14159) * (64) * (h)
128 = 201.1 * h
128 / 201.1 = 201.1 * h / 201.1
0.636 = h
0.636 = 2 / (pi)

Answer 4

you just do 2/3.1415..... and you get .6366197724

or set it up like this:
128=3.141592654(8^2)(H)
it gets you the same answer.

Answer 5

plug everything in and then solve for h.