Right Triangles
 A right triangle, or rightangled triangle, is a triangle in which one of the corners has an angle of 90^{o}

For example:

To show that it is a 90^{o} angle we add a little square in the corner:

The longest side of the triangle is always the one opposite the right angle. This side is called the 'hypotinuse':
Pythagorean theorem
 The pythagorean theorem can be used to find the length of the hypotinuse given the length of the other two sides.

if a, b, and c are the length of the three sides:

The pythagorean theorem states that:
c^{2} = a^{2} + b^{2}
Example

if a = 4 and b = 3, calculate the length of c

Using the pythagorean theorem, we know that:

Now we just solve for c:

Finding other sides
 We can also use the pythagorean theorem to find the length of any side, given that we know the other two.

For example: if a = 8 and c = 10, calculate the length of b

Using the pythagorean theorem, we know that:

Now we solve for b:

Code
import math a = 4 b = 3 c = math.hypot(a, b) print(c) # prints: 5