# How to find the perimeter of a right-angle triangle with one side missing?

Perimeter is defined as the length of the total boundary of a shape.

## Answer: We can find the missing side and the perimeter of a right-angled triangle using the Pythagoras theorem.

Let us understand this with an example.

**Explanation:**

In a right-angled triangle, if the hypotenuse = 5 units and base side = 4 units.

If 'a' and 'b' are the sides of a right-angled triangle and 'c' is the hypotenuse, then using the Pythagoras theorem,

c^{2} = a^{2} + b^{2}

5^{2} = 4^{2} + b^{2}

25 = 16 + b^{2}

9 = b^{2}

b = 3

The other side is 3 units.

Now, perimeter of triangle = a+b+c

P = 3 + 4 + 5

P = 12

Perimeter = 12 units