Abc is a straight line. the length of ab is four times the length of bc. ac = 75cm. work out the length of ab.

Given to us,

ABC is a straight line,

the length of AB is four times the length of BC,

AC = 75cm.

As given to us, the length of AB is four times the length of BC. therefore, we can write it as, AB = 4(BC), which is equation 1 for us.

Also, the length of the ABC will be constant. therefore, 75 cm. and the line AB and BC will together form the line ABC(AC). thus, we can write it as,

AB + BC = AC

substituting the value of AB from equation 1 we get in equation 2,

4(BC) + BC = AC

5(BC) = AC

5(BC) = 75

BC = 15 cm.

Substituting the value of BC in equation 1, we get,

AB = 4(BC)

AB = 4 x 15

AB = 60 cm

Hence, the length of line AB is 60 cms.

Learn more about Lines:

link

AB = 60 cm

Step-by-step explanation:

AB + BC = AC

let the length of BC = x then AB = 4x, hence

4x + x = 75

5x = 75 ( divide both sides by 5 )

x = 15

AB = 4x = 4 × 15 = 60 cm