Question

please answer as soon as possible ​

Answer 1

Answer:

I can understand what is that I am sorry

Answer 2

Step-by-step explanation:

Given:

A ∆ ABC, in which sides are AB=BC= AC= a units

and AD is perpendicular to BC ,

In ∆ADB ,

AB²= AD²+ BD²     (by Pythagoras theorem)

a² = AD² + (a/2)²   [BD= 1/2BC, since in an equilateral triangle altitude AD is  perpendicular bisector of BC ]

a²- a²/4 =AD²

=( 4a²-a²)/4 = AD²

= 3a² /4 = AD²

3AB²/4= AD²

[ AB= a]

3AB²= 4AD²

So, the first option is correct.