Question

The length of a straight line ABC is 5m. If AB:BC= 2:5, find the length of AB

Answer 1

Answer:

$\frac{10}{7}\approx 1.43\text{ m}$.

Step-by-step explanation:

We have been given the length of a straight line ABC is 5 m. We are asked to find the length of AB, when $AB:BC=2:5$.

We can represent our given ration as:

$\frac{AB}{BC}=\frac{2}{5}$

We can write above ratio in terms of AC as:

$\frac{AB}{AB+BC}=\frac{2}{2+5}$

$\frac{AB}{AC}=\frac{2}{2+5}$

Upon substituting $AC=5$, we will get:

$\frac{AB}{5}=\frac{2}{7}$

$\frac{AB}{5}*5=\frac{2}{7}*5$

$AB=\frac{2*5}{7}$

$AB=\frac{10}{7}=1.42857$

Therefore, the length of AB is $\frac{10}{7}\approx 1.43\text{ m}$.

Answer 2

AB/BC = 2/5
AC=5

AB/(AB+BC)=2/(2+5)
AB/AC=2/7
AB/5=2/7

AB=10/7=1.4286 m