Using Pythagoras theorem to find side lengths of a triangle

Pythagoras theorem can sound quite intimidating but it involves remembering just one equation and using it like a rule. This rule can only be used on right-angled triangle. Just remember c² = a²+b². Each letter is one side of a triangle, with C being the longest side, which is called the hypotenuse. It just means the length of side C squared must equal the length of side A squared PLUS the length of side B squared. So to find the length of the hypotenuse of a triangle with one side equal to 5 and the other equal to 3, we fill in the equation. 3²+5² = c² , this becomes 9 + 25 = c ² , then c² = 34 so c would equal the square root of 34.