Quantitative Comparisions

[patrakakali79]

Isosceles Triangle DEF lies in the xy - plane with D at (-3,0) and F at (3,0).The length of DE is 5.

Column A Column B
y co-ordinate of point E 4



Source: Kaplan GRE

[tommywallach]

Hey Patra,

I can't really draw in here, so I'll have to explain it.

Draw a coordinate graph, and place the two points you know. Now, let's imagine the coordinates of the final point (E) are at (0,4). This is logical, because Column (B) says "4", which is always a hint that we should think about that number.

Now what you'll see is that you've built an isosceles triangle. We know that DE has to be 5, and that's actually the case here! We know that because if you split this triangle down the middle, you're left with two 3-4-5 right triangles (one on either side of the y-axis). So this is a legit triangle, and the y-value of (E) is 4.

But we could ALSO put point (E) at (0, -4). The distance from D to E would still be 5 (because we would still have two 3-4-5 triangles), but the y-value of (E) would be -4. This means the answer is (D). We have one example where the two columns are equal, and one example where Column B is bigger than Column A.

-t

[patrakakali79]

thanks a lot for the explanation.

[tommywallach]

Glad to help!

-t