Question

1. The diagonal length of a laptop computer screen is advertised as 45 cm. the width of the screen is 25 cm. Work out the length of the laptop computer screen. Give your answer to the 3 significant figures.

a) 37.4 cm
b) 51.5 cm
c) 4.47 cm

Answer 1

a

Explanation:

The diagonal is the hypotenuse of a right triangle with the width and length being the legs.

let l be the length

Using Pythagoras' identity in the right triangle , then

l² + 25² = 45²

l² + 625 = 2025 ( subtract 625 from both sides )

l² = 1400 ( take square root of both sides )

l =
`√(1400)` ≈ 37.4 cm ( to 3 significant figures )

The length is approximately 37.4 cm

Answer 2

116

Explanation:

25 x 45 = 1,125