GRE Math Practice: Geometry - Example 4

Uploaded by MagooshGRE on 01.06.2011

Alright, to begin, the question tells us that AO is the same length as OB, so we'll add
that information to our diagram
Now in this question, we're comparing the area of the semicircle to the area of the
Now if the question tells us that O is the center of the circle, that means AO must be
the radius of our circle,
And since OB has the same length as AO, OB must also be the radius of our circle.
So if we extend our circle, the tip of our triangle will just touch the edge of our circle.
Now for our last step here, we need to recognize that the area of our lower semicircle is equal
to the area of the upper semicircle.
And since our triangle fits inside of this semicircle, the semicircle must have a greater
So column A is greater than column B, which means our answer is A.