Pythagorean's theorem says the hypotenuse of a triangle is A^2+B^2=C^2 in this case I'll put the L,W, and D so it's easy to understand. L^2+W^2=D^2 is the exact same formula as above and is how we will solve this. (30^2)+(10^2)=1000 then we take the square root since 1000=D^2, and we get 36.62 as D.