Question

The point C divides the line segment AB in the ratio 3:7. Find the length of AB (in cm) if the line segment BC is 3.5 cm long -

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Answer 1

$\frac{AC}{BC}$ =$\frac{3}{7}$

Therefore, $\frac{AB}{BC}$= $\frac{BC}{BC}$ + $\frac{AC}{BC}$ = 1+ $\frac{3}{7}$ = $\frac{10}{7}$

$\frac{AB}{BC}$ = $\frac{10}{7}$. So, AB=BC $\times$ $\frac{10}{7}$ = 5 cm.