Question

2 no.plz pls please let me know​

Answer 1

Step-by-step explanation:

ABC is a right angled at B and D is the midpoint of BC.

In ∆ABD,

AD²= AB²+BD²    ---- (1)

In ∆ ABC,

AC²= AB²+BC²   ---- (2)

From equation (1)

AD²= AB²+ (BC/2)² [D is the midpoint of BC]

AD²= AB²+ BC²/4

AD²= AB²/1+ BC²/4

4AD²= 4AB²+ BC²

BC²= 4AD²-4AB²   ---- (3)

Using the value of BC² in (2), we get

AC²=AB² + 4AD² - 4AB²

AC²=AB²- 4AB + 4AD²

AC²= 4AD²- 3AB²

Hope it helps!