Q.In triangle ∆ABC, a straight line parallel to side BC intersects sides AB and AC at points X and Y respectively. If AX = 2.4 cm, AY = 3.2 cm, and YC = 4.8 cm, find the length of AB.
In triangle ∆ABC, XY ∥ BC and AC = AY + YC = 3.2 + 4.8 = 8 cm
Because XY ∥ BC in ∆ABC,
∴ \( \frac{AX}{AB} = \frac{AY}{AC} \)
i.e., \( \frac{2.4}{AB} = \frac{3.2}{8} \)
i.e., \( AB = \frac{2.4 \times 8}{3.2} \)
i.e., \( AB = 6 \)
∴ AB = 6 cm