I need to write a proof and prove that: any triangle inscribed in a semicircle is a right triangle.

I realize that it is right, but I am unsure how to prove that it is true.

Can anyone help me with an idea of where to start?

Thanks.

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- Mar 31st 2009, 10:23 AMCalaghanNeed help for geometry proof
I need to write a proof and prove that: any triangle inscribed in a semicircle is a right triangle.

I realize that it is right, but I am unsure how to prove that it is true.

Can anyone help me with an idea of where to start?

Thanks. - Mar 31st 2009, 11:19 AMPlato
Realize that the diameter of the circle is the hypotenuse of the triangle.

Any inscribed angle in a circle measures one-half the intercepted arc.

But that is the “other” semicircle which measures $\displaystyle \pi$. - Apr 1st 2009, 06:56 AMCalaghan
I'm confused with what the intercepted arc is and therefore both the second and third lines confuse me.