"For the triangle shown above, where A, B, and C"

[Guest]

This is a DS question from the 4th CAT exam, question #4.

"For the triangle shown above, where A, B and C are all points on a circle, and line segment AB has length 18, what is the area of triangle ABC?

(1) Angle ABC measures 30 degrees.
(2) The circumference of the circle is 18 (pie)

The answer for this question is C, both statements together are sufficient. The answer gives as explanation the fact that in order to find the area of the triangle, we need to know the base and the height (that is how I rephrased it, too). But, then it proceeds to explain that we need to first prove that it is a right triangle so that we can assume that CB is the base and AC is the height (AB, the hypotenuse, is 18).

I thought that for inscribed triangles in circles with their three points on the circle, a triangle HAD to be a right triangle. This answer explanation contradicts that...can you please explain?

[Abhimanyu Sood]

I cannot comment on the solution to this question,since i do not have the figure......

But I can add a little more to your statement "I thought that for inscribed triangles in circles with their three points on the circle, a triangle HAD to be a right triangle. This answer explanation contradicts that...can you please explain?"

A triangle inscribed in a Semi Circle is a Right angle traingle,this does not stands true for whole circle.....I hope this helps u out.......


What I can visualize from ur question is that the points of the triangle are not in semi circle and if thats the case then Answer is C

[kdcui]

Guest,

You can inscribe any triangle into a circle (you cna just as easily make an equilateral triangle, which has 60 angles).

I had a question on that same problem, though somewhat different:
http://www.manhattangmat.com/forums/inscribed-triangle-data-suff-could-someone-explain-t3224.html

[RonPurewal]

hi - please post the picture from this problem. since this is from our exam, you should be able to take the image directly from the site and upload it to an image hosting site such as http://xs.to/.
thanks.