Question

What’s the answer to this?

Answer 1

Since the triangle is equilateral, all its angles are equal to 60°

AO is the bisector⇒∠OAD = 30°

AO is the hypotenuse, ∠OAD = 30°⇒

OD=5*2=10m

By the Pythagorean theorem

`10^2=AD^2+5^2\\AD=√(100-25) \\AD=√(75)`

`AC=AD+DC=2√(75)=10√(3)`

`S=(a^2√(3) )/(4)`

`S=((10√(3))^2√(3) )/(4) =(300√(3) )/(4) =75√(3) m^2`

Answer: A)
`S=75√(3)`m²

P.S. Hello from Russia and sorry for my bad english :^)