Question

Find the area of an equilateral triangle (regular 3-gon) with the given measurement.

6-inch radius

A = sq. in.

i have 18sqrt3but idk if its right or not please help me

Answer 1

hmmm, well if it has a 6 inch radius, then that means that 6 inches is half of the height

Answer 2

the area of an equilateral triangle is
\[A=s ^{2}\sqrt{3}/4\]

Answer 3

right, but what is the length of S?

Answer 4

here is a good explanation about how to think about it: http://en.allexperts.com/q/Geometry-2060/area-equilateral-triangle-given.htm

Answer 5

I'm guessing s=6 in this case since it's the only dimension we're given.
As for your result, it seems close but using the given area for s=6, your answer would be
\[9\sqrt{3}\]

Answer 6

s=length of one side of the equalateral triangle, not the radius

Answer 7

using trig though you can follow the link I pasted to get the length of s, given the radius dissects the angles in known ways

Answer 8

no the radius would b half the height. there fore the base would b
b=2(r/tan(30))
the height h=2r
so
A=1/2(2r)^2(1/tan(30))

Answer 9

i already have 9sqrt3 for the side i needd the radius