D and E are points on the sides AB and AC respectively of a ΔABC such that DE || BC. If AB = 13.3 cm, AC = 11.9 cm and EC = 5.1 cm, find AD.

Question

Philoid · Accepted Answer

Given: AB = 13.3 cm, AC = 11.9 cm and EC = 5.1 cm.

Applying Thale’s Theorem,

Since we need to find DB first, we add 1 on both sides

⇒

⇒ DB = 5.7

AD is given by,

AD = AB – DB

⇒ AD = 13.3 – 5.7

⇒ AD = 7.6 cm

Hence, AD is 7.6