SOLUTION: Hi, could you guide me about my mistake? What are the lengths of sides of an equilateral triangle of height 3 cm? My solution is: I regard if I intersect this triangle to two

Algebra ->  Triangles -> SOLUTION: Hi, could you guide me about my mistake? What are the lengths of sides of an equilateral triangle of height 3 cm? My solution is: I regard if I intersect this triangle to two       Log On


   

Question 203430: Hi, could you guide me about my mistake?
What are the lengths of sides of an equilateral triangle of height 3 cm?
My solution is:
I regard if I intersect this triangle to two right triangles I can use of following formula which I remember of high school:
Sin alpha = opposite side/hypotenuse
I consider: Sin 60=h/c
So I will have radical1/2= 3/c
therefore c =6 = a = b
but its not ok cause 3^2 +^2 is not equal to 6^2!
one more thing: could you tell me do I can use of Sin alpha = opposite side/hypotenuse
and Cos alpha = adjacent side/hypotenuse for all the angles in a triangle? even for a right angle?

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
think you have the wrong value for sin(60º) ___ it is [sqrt(3) / 2]

so, c = 6 / sqrt(3) or c = 2 sqrt(3)


yes, the general sin and cos equations are right
___ but they DON'T work for the right angle because -- which side is adjacent?