Question

In $\Delta ABC,DE||AC,IFAD=2.4cm,DB=4cm,BE=5cm$ then find the length of BC

Answer 1

Let $EC=x$ in the figure.

In $\Delta ABC$,

$DE\parallel AC$

So,

$\frac{BD}{DA}=\frac{BE}{EC}$ ( A line drawn parallel to one side of triangle divides other sides in the same ratio. )

$\frac{4}{2.4}=\frac{5}{x}$

$x=\frac{5\times 2.4}{4}$

$x=\frac{12}{4}=3$ cm

Now,

$BC=BE+EC=5+3=8$ cm