ABC is a straight line.

+

H

B

C

The length AB is five times the length BC.

AC = 90 cm.

Work out the length AB.

AB = cm

AB = 75 cm

Step-by-step explanation:

Since ABC is a straight line, then

AB + BC = AC

let BC be x then AB = 5x and summing gives

5x + x = 90

6x = 90 (divide both sides by 6)

x = 15

Thus

AB = 5x = 5 * 15 = 75 cm