Question

ABC is right angle triangle with ACB=90*, BC=12cm, AB=15cm, and CD=5cm.
Find the lengths of AD.​

Answer 1

In Triangle BDC

BD²= BC²+CD²

BD² = 12² + 5²

BD² = 144 +25

BD² = 169

BD = 13cm

In Triangle ABC

AB²= AC²  + BC²

15² =  AC² + 12²

225 = AC² + 144

AC² = 225 - 144

AC² = 81

AC = 9

We know that AC = AD + CD

SO,

9 = AD + 5

AD = 9-5

AD = 4