A computer monitor is 20 inches wide. The aspect ratio, which is the ratio of the width of the screen to the height of the screen, is 16:9. What is the length diagonal of the screen, to the nearest whole inch.

Answer 1

W = Wide

H = height

D = Diagonal

W / H = 16 / 9

20 / H = 16 / 9 Multiply both sides by 9

20 * 9 / H = 16 * 9 / 9

180 / H = 16 Multiply both sides by H

180 * H / H = 16 * H

180 = 16 H Divide both sides by 16

180 / 16 = 16 H / 16

11.25 = H

H = 11.25 in

Pythagorean theorem :

D = sqroot ( W ^ 2 + H ^ 2 ) =

sqroot ( 20 ^ 2 + 11.25 ^ 2 ) =

sqroot ( 400 + 126.5625 ) =

sqroot ( 526.5625 ) =

22.9469497 in

approx. 23 in