Step-by-step explanation:
step 1. make a triangle with the line being the hypotenuse. let a be the base, b the height, and c the hypotenuse.
step 2. a^2 + b^2 = c^2 pythagorean theorem
step 3. 4^2 + 3^2 = c^2
step 4. c^2 = 25
step 5. c = 5 (answer).
