Data Sufficiency

Is the triangle to the right ( ' see attachment below) isosceles?

st(1) a=b
st(2) c is not equal to b

I chose C, as st(1) implies only two sides equal and no information about the third side, hence if the third side is equal to two sides then the triangle is equilateral Not Sufficient
st(2) implies only inequality of c and b Not Sufficient
Combined st(1&2) Sufficient

However OA is A

equilateral is an isosceles triangle. more specifically, equilateral is a special isosceles much like a rhombus is a parallelogram.

I resolved this problem by looking definition at Moron's math site

` isosceles triangle --> at least two sides are equal

Equilateral just means that two sides are equal(or all three)

In the case with the first stem. A=B. Therefore, two sides are equal and you have an isoscelese

There is no data to tell about the angle ? HOw can we say that it right angled triangle ?

PLease kindly clarify my doubt ?

You answered it yourself.

isosceles triangle --> at least two sides are equal . It could be three sides equal as well.

Hi,

here's a good general takeaway from this question:

special cases of general shapes still count as general shapes.

For example, a quadrilateral is a polygon; a parallelogram is a quadrilateral and a polygon; a rectangle is a parallelogram, quadrilateral AND a polygon; and a square is a rectangle, parallelogram, quadrilateral AND a polygon.

agree with Stuart, i read somewhere,
"every equilateral triangle is also isosceles"

I hope this is not from bench mark gmat ?

bblast wrote:agree with Stuart, i read somewhere,
"every equilateral triangle is also isosceles"

I hope this is not from bench mark gmat ?

this question is from GMAT Prep software by nova press.