Difference between revisions of "Base Angle Theorem"
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| − | The ''Hinge | + | The '''Hinge Theorem''' states that in an [[isosceles triangle]], the measures of the angles opposite the equal-measuring sides are equal. |
==Proof== | ==Proof== | ||
Revision as of 16:52, 31 August 2008
The Hinge Theorem states that in an isosceles triangle, the measures of the angles opposite the equal-measuring sides are equal.
Proof
Since the triangle only has three sides, the two equal-measuring sides must be adjacent. Let them meet at vertex 
. Now we draw height 
to 
. From the Pythagorean Theorem, 
, and thus 
is similar to 
, and 
.
