Question

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

Answer 1

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