I really need help with this problem. If anyone could at least guide me in the right direction I'll be grateful!

Show that among all isosceles triangles whose equal sides have equal length L, the triangle of largest area is a right triangle

Question

I really need help with this problem. If anyone could at least guide me in the right direction I'll be grateful! 
   
Show that among all isosceles triangles whose equal sides have equal length L, the triangle of largest area is a right triangle

terenzreignz · Answer

try it... get the area of an isosceles triangle with two sides of length L and θ the angle between them

terenzreignz · Answer

L being a constant, of course.

anonymous · Answer

How would I get the area and angle without any numerical values? I thing not having any numbers to work with is my biggest problem right now...

terenzreignz · Answer

Algebra :)
Let's draw an isosceles triangle, only, let's draw it like this, it's easier to see things this way...


L is what's called a parameter... not quite a variable, for all intents and purposes, it's a constant.

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terenzreignz · Answer

now the angle|dw:1366032623037:dw|

terenzreignz · Answer

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anonymous · Answer

Ok I somewhat see where you are going... Is there some kind of equation that goes with this?

terenzreignz · Answer

Of course :)
What's the formula for the area of a triangle?

anonymous · Answer

1/2bh

terenzreignz · Answer

Yeah... so in this case, our base is L, right?

anonymous · Answer

Yep

terenzreignz · Answer

What's our height (h) ?|dw:1366032936354:dw|