Question

In the figure given below, 𝐷𝐸∥𝐵𝐶. Find the length of side 𝐴𝐷, given that 𝐴𝐸 = 1.8 𝑐𝑚, 𝐵𝐷 = 7.2 𝑐𝑚 and 𝐶𝐸 = 5.4 𝑐𝑚.

Answer 1

Apply Basic Proportionality Theorem (BPT) in ΔABC.
Given: DE || BC
So, $\frac{AD}{BD}=\frac{AE}{CE}$ (i) (1 Mark)
Put the values of AE = 1.8 cm , BD = 7.2 cm, CE = 5.4 cm in equation (i), we get
$\frac{AD}{BD}=\frac{AE}{CE}$
$\frac{AD}{7.2}=\frac{1.8}{5.4}$
⟹ $AD=2.4cm$
(1 Mark)
Hence, AD = 2.4 cm.