So that is a 90 degree angle, a 90 degree angle and that is a 90 degree angle over there

This is a 90 degree angle here.

So we have a 90 degree angle.

This is a 90 degree angle right here.

This is the 90 degree angle right here.

This is a perfect 90 degree angle by nature.

It intersects this base at a 90 degree angle

One extremely useful Angle A Tron is the 90 degree Angle A Tron.

This 90 degree angle kind of opens into this longest side.

So the way I drew it right here, this is our 90 degree angle.

You see the diagonals intersect at a 90 degree angle so we've just proved

90 degree rotation speed

And I know it's the height because they told me it's a 90 degree angle.

It's a 90 degree angle, if you've been exposed to the idea of angles already.

So a right triangle is a triangle that has a 90 degree angle in it.

It's got 90 degree corners.

And since that is a triangle that has a 90 degree angle, it's a right triangle.

And you can see from our measure right over here that that gives us a 90 degree angle, which is a very interesting angle that shows up many times in geometry and trigonometry, and there's a special word for a 90 degree angle it is called a right angle.

An angle of 90 degrees is called a right angle.

Well, if this angle here is alpha, then this much be a 90 degree angle, because a radius intersecting with a tangent line always forms a right angle.

And remember, the c that we're dealing with right here is the side opposite the 90 degree angle.

This function transforms a radian angle to a degree angle.

This function transforms a degree angle to a radian angle.

This pink angle is supplementary to this 110 degree angle.

less than 90 degrees you have an acute angle, at 90 degrees you have a right angle,

They're asking us to draw a right triangle, so that means it has to have a 90 degree angle.

The longest side of a right triangle, the side that is opposite the 90 degree angle, is called the hypotentuse.

So the fact that it's perpendicular means that this line will make a 90 degree angle where it intersects with AB.

If this angle here is 90 then this angle over here is also going to be 90 because they are supplementary

And that longer side is call the hypotenuse. And in all cases, the hypotenuse is the side opposite the 90 degree angle.

So we know that a squared plus 3 squared is equal to the hypotenuse squared, the side opposite the 90 degree angle.

So this pink angle theta plus this green angle must be equal to 90 degrees

When we do, however, make a turn into a side street, our mind tends to adjust that turn to a 90 degree angle.

There's that 90 degree turn. He's out over the channel.

It's easy to get a 90 degree angle a tron, and if I take a third of a third of that, that's a ninth of 90 which is another 10 degrees.

Now you can make puzzles for yourself. Say you make a 60 degree Angle A Tron, and a 135 degree Angle A Tron,

36 plus this angle have to be equal to 90.

So then we have this angle plus 90 degrees plus this angle have to equal 180.

Suppose we draw a line at a 45 degree angle,

These sides are perpendicular, or the angle between them is 90 degrees, or it is a right angle.

And the way to tell is that the longest side in a right triangle, and this only applies to a right triangle, is the side opposite the 90 degree angle.

If you've never seen a 90 degree angle before, the way to think about it is, if this side goes straight left to right, this side goes straight up and down.

You can see the Lhotse face is in profile, it's about a 45 degree angle.

From here, it's about 1,500 feet up at a 30 degree angle to the summit.

That tells me that the measure of angle AEB is equal to the measure of angle CEB which must be equal to 90 degrees