math
posted by Evelyn on .
screen sizes (TVs, computers) are given by measuring the length of the diagonal. If the base length of a 40inch TV is 32", what is the surface area of the TV screen? (think about what you need to know to compute the area of a rectangle)

so, did you think about what you need to know? Length and Height.
Now think back to the Pythagorean Theorem.