9.920 is the answer to your question
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
Answer: A) m²
P.S. Hello from Russia and sorry for my bad english :^)
Where is the graph ??
Please provide the graph so that we can answer your questions ....