Using Pythagoras Theorem find the length of the hypotenuse of a right triangle where a=7 cm and b=11 cm. Round to the nearest tenth

Pythagos Theorem states that 

a^2 + b^2 = c^2

So using the figures we are given the equation would look like this:

7^2 + 11^2 = c^2

We square the numbers we can and then get:

49 + 121 = c^2

We add the left hand side up and get:

170 = c^2

We then must isolate the variable and since c is suared the only way to do that would be prreform the opposite function and take the square root of both side. Since 170 is not a perfect square we will put it into our calculators and see what we get.

The square root of 170 is approximately 13.038404...

Since the problems asks that we round to the nearest tenth we look at both that number and the one right behind it:

13.03

Since 3 is smaller than 5 we round down giving the answer of approximately 13 cm