Question 271201
find the length and width with a ratio of 16:9 of a rectangle that has a 42 inch diagonal

Let W be the width and L the length of the rectangle. We know then that:

16/9 = L/W

L = (16/9)*W

Then using the Pythagorean Theorem we have:

L^2 + W^2 = 42^2 and
[(16/9)*W]^2 + W^2 = 42^2

Solve the above for W and then calculate L = (16/9)*W