ABC is a straight line

The length of AB is four times the length of BC.

AC = 75 cm

Work out the length of AB.

Answer: Length of AB = 60cm

Step-by-step explanation: ABC is a straight line

Let the length of AB and BC be x and y respectively

x = 4y

y = y

∴4y+y = 75

5y=75

→y = 15

→x = 4y

∴x = 4*15 = 60cm

∴AB (x) = 60cm

∴BC (y) = 15cm

AB = 60 cm

Step-by-step explanation:

AC = AB + BC

75 = AB + AB/4

4*75 = 4AB + AB

300 = 5AB

AB = 300/5

AB = 60 cm