winter wrote:In isosceles triangle RST what is the measure of angle R?
1) The measure of angle T is 100
2) The measure of angle S is 40
Answer is A.
How do we know which sides of a triangle are equal?
(1) Angle T = 100. Given that RST is an isosceles triangle and in an isosceles triangle, 2 angles are equal.
But none of the other two angles can be equal to angle T, since the sum of the angles in a triangle is 180º.
It means the other two angles S and R are equal. Let angle S = angle R = x
2x + 100 = 180 implies x = 40. So, angle R = 40º.
So, (1) is SUFFICIENT.
(2) Angle S = 40º, but here angle S can be equal to R or it can be equal to angle T, which is not given.
Hence, (2) is NOT SUFFICIENT.
The correct answer is (A).Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
