∆ABC is a right angled at B and D is a point on BC if AD = 18cm BD = 9cm and CD =4cm Find AC

Question

asked May 5, 2017 72.8k views

1 Answer

Rightstuff · Answer 1 · 2017-05-09T05:11:15+0000

In triangle, ABD,

AD²= AB²+BD²

AB² = AD²-BD²

AB² = 18²-9² = 324-81 = 243

AB = √243

In triangle, ABC,

AC² = AB²+BC²

AC² = (√243)²+(13)²

AC² = 243+169

AC = √412

AC = 20.29