Question

ABC is a triangle and PQ is parallel to BC.

BC = 12.6 cm, PQ = 8.4cm and AQ = 7.2 cm.
Find AC.
(i know that parallel lines divide triangle sides proportionally, but can someone do a detailed step on AC)

Answer 1

Similar triangles ( reduction)

The ratio of the sides of the two figures are in a constant ratio
ie. BC/AC = PQ/AQ
12.6/AC = 8.4/7.2
Cross multiply
8.4AC =12.6x7.2
8.4AC = 90.72
Divide through by 8.4
AC= 10.8 cm