Many television screens are rectangles that are measured by the length of their diagonals. The ratio of the horizontal length to the height in a standard television screen is 4:3 What is the horizontal length (in inches) of a ``25-inch'' television screen?
+128474 Let the height = H then the horizontal length = (4/3)H
Using the Pythagorean Theorem :
H^2 + [ (4/3)H ]^2 = 25^2
H^2 + (16/9) H^2 = 625
(25/9)H^2 = 625
H^2 = 625 ( 9 / 25)
H^2 = 25 * 9
H^2 = 225 take thw positive root
H = 15
And the horizontal length = (4/3)H = (4/3)(15) = 20 in
