Carcass wrote:
Point O is the center of the semicircle. If ∠ BCO = 30 ° and
BC=6√3 what is the area of triangle ABO?
Attachment:
GRE exam - Point O is the center of the semicircle..jpg
A.
4√3B.
6√3C.
9√3D.
12√3E.
24√3triangle ABC is a right angled triangle at A, and ∠ BCO = 30 °, so ABC is 30-60-90 triangle and sides are in ratio 1:
√3:2
now opposite 60 is side
BC=6√3, so AB=6 and AC=12=2*radius.... radius = 6
Let us see OAB..
As we can see AB=6 and OA=OB=radius=6
so it is an equilateral triangle with side 6..
area =
(√3/4)∗62=9√3C