Geometry help

[daniellagirl89]

I'm having some trouble with geometry review, if you can help that'd be great.

The base of a pyramid is a square with sides of length 4 cm. If the volume = 80 cm3, what is the height? ___ cm


Find the value of x: (2x) / 7 = (x - 1) / 3


Given Triangle RST is similar to Triangle DEF. If measure Ang E = 38, measure Ang R = 43, and measure Ang T = 7x + 8, then x = ?

 

[skeeter]

I'm having some trouble with geometry review, if you can help that'd be great.

The base of a pyramid is a square with sides of length 4 cm. If the volume = 80 cm3, what is the height? ___ cm

V = BH/3, where B = pyramid base area and H = pyramid height


Find the value of x: (2x) / 7 = (x - 1) / 3

cross multiply ...
3(2x) = 7(x-1)
can you finish?


Given Triangle RST is similar to Triangle DEF. If measure Ang E = 38, measure Ang R = 43, and measure Ang T = 7x + 8, then x = ?

similar triangles have congruent angles ... angle E = angle S, angle R = angle D, and angle T = angle F.

 

[jwpaine]

Hi. I'll do the first two.. someone else can help can tutor on the third

Question #1.)
volume of pyramid = (1/3) * area_of_base * height
You already know your area and your area of base... so solve the literal equation for height.

Question #2.) solve \(\displaystyle \L \frac{2x}{7} = \frac{x-1}{3}\)

Cross multiply:

\(\displaystyle \L 7(x - 1) = 3(2x)\) Complete this equation...easy now, right?

Hope this helps,
John.


EDIT: skeeter! Yes...I was in fact writing for that length of time

 

[SaxyTimmy]

I'm having some trouble with geometry review, if you can help that'd be great.

The base of a pyramid is a square with sides of length 4 cm. If the volume = 80 cm3, what is the height? ___ cm


Find the value of x: (2x) / 7 = (x - 1) / 3


Given Triangle RST is similar to Triangle DEF. If measure Ang E = 38, measure Ang R = 43, and measure Ang T = 7x + 8, then x = ?

Note: R=Angle R

We know that two angles of RST must be 38 and 43. Because they are similar. If they are similar we know that all angles in each of the triangles is the same. We also know that all angles in a triangle add up to 180.

From this we can get:

180-43-38=T
180-43-38=7x+8

So you know if you got the right answer x=13... but learn how to do that and if you need more help... just ask again

I hope that helps and more so i hope i am right