Now, this triangle right here is an isosceles triangle.

Geometric Isosceles Triangle

An isosceles, let me write this, this is a right isosceles, i sos ce les triangle.

Or another way to think about it is, if I have a right triangle that is also isosceles ,so a right triangle that is also isosceles.

It's an isosceles triangle

Kind of like an isosceles triangle.

But you can have a right angle, you can have a right triangle that is isosceles.

So if I had another isosceles triangle.

This is an upside down isosceles triangle, this is a right side up one.

So the ratio of the sides and the hypotenuse, in a 45 45 90 triangle, or a right isosceles triangle.

So if you have a right isosceles triangle, whatever the two legs are, they're gonna have the same length, that's why it's isosceles.

Base angles are equivalent on an isosceles triangle.

But we know that they're definitely isosceles triangle

This becomes an isosceles triangle again, very shaky.

You could think of an isosceles triangle, over here.

So a right isosceles triangle can also be called, and this is the more typical name for it

And I can make the argument, but basically we know that RP, since this is an isosceles trapezoid, you could imagine kind of continuing a triangle and making an isosceles triangle here.

I haven't seen the definition of an isosceles triangle anytime in the recent past.

This is an isosceles triangle, so the two legs are going to be the same.

They are going to be the same to each other, because this is an isosceles triangle.

Triangle AMO is a right triangle

so we're able to using constructing this triangle here we're able to both show its a similar and to construct this larger isosceles triangle to show

And the reason why that is interesting is it let's us know that this is an isosceles triangle

An altitude by definition is going to be perpendicular down here. Now, an isosceles triangle is perfectly symmetrical.

So even thought, it doesn't look that way based on the way, its drawn. This is actually an isosceles triangle.

Because these two base angles it's an isosceles triangle the two legs are the same so are two base angles

And isosceles triangle means that that side is equal to that side and that angle is equal to that angle.

If you drop an altitude from the the top, or the unique angle, or the unique vertex in an isosceles triangle you will split it into two symmetric right triangles.

Geometric Right Angle Triangle

It's a right triangle.

So whatever isosceles triangle, if you have your 2 legs of it, the 2 base angles are going to be congruent

larger triangle right up there

This is a right triangle.

The sum of the square roots of two sides of an isosceles triangle is equal to the square root of the remaining side.

AO is it's hypoteneuse triangle OMC is a right triangle and this is it's hypotenuese right there

Well we have right triangle here.

We have a right triangle here.

So this is a right triangle.

Right triangle ABC is pictured below.

But this forms a right triangle.

Look at this triangle right here.

So this is a right triangle.

So we have a right triangle.

Say we have a right triangle.

let's construct ourselves a right triangle.