Geometry volume of prism

[DEV]

Can you help me find the volume of a prism whose base is an equilateral triangle with a side of 20 and whose length is 12?

 

[tkhunny]

Yes, but in order to "help", you must do something. What have you done? What methods hae you at your disposal? What class are you in and why?

 

[DEV]

in Geometry. first I tried using the prism formula- V=Bh, and then i plugged in (1/2)(20 x 12)(12) in the place of B. Now i do not know what to do.
I looked at the answer key and I have no idea how my teacher got that answer because it contained radicals and i don't know where those came from

 

[tkhunny]

Youneed the area of the Equilateral Triangle.

1/2 * Base * Height.

You have Base = 20

Draw an altitude in your equilateral triangle.
You should find this to be also a perpendicular bisector!
You should know something about the angle measures of an equilateral triangle.
You should know something about a few special traingles, such as 30-60-90.

Let's see what youget.