We are given the following triangle
where we want to solve for x. Note that this triangle is a right triangle. Therefore, the missing side is the hypotenuse of the triangle.
To find the measure of the hypotenuse, we are going to use pythagora's theorem, which states
Given the triangle
we have the equation
in our case, we have x=c, a=12, b=16. So we have the equation
So, if we apply the square root on both sides, we get
however, as x is a distance, it must be a positive number. So we have that