If I have a function f(x)=2x+3, what is f(4)?

Refer to the attached figure. We know that AB is 16 inches. We also know that AD=BD=10 and AE=BE=17

We're interested in DE, which we can compute as CD+CE

To compute CD, we can observe that ACD is a right triangle, and that AC is 8 inches long (it's half the base) and AD is 10 inches long (given).

So, by Pythagorean's theorem, we have

Similarly, we have

So, we have