Televisions and computer screens are usually advertised based on the length of their diagonals. If the height of a computer screen is 11 in. and the width is 14 in., what is the length of the diagonal? Round to the nearest inch.

TV and Computer screens are rectangular in shape.

If we know the height and the width of the screen, we can apply Pythagoras Theorem to determine the diagonal of the screen. The diagonal would be represented by the hypotenuse of the triangle.

Height = 11 inch

Width = 14 inch

By the Pythagoras Theorem, we know that Height² + Width² = Hypotenuse²

⇒ 11² + 14² = Hypotenuse²

⇒ 121 + 196 = Hypotenuse²

⇒ Hypotenuse² = 317

Taking square root to determine the Hypotenuse

⇒ Hypotenuse = √317

⇒ Hypotenuse = 17.80449381 ...

Round up

⇒ Hypotenuse = 18 inch

Hence, the diagonal of the screen is 18 inch