DSQ: Calculating the length of the diagonal of a rectangle - GMAT Quantitative

Card 1 of 40

0
Didn't Know
Knew It
0
1 of 2019 left
Question

Export-png__5_

What is the length of the diagonal of rectangle ?

(1)

(2) and

Tap to reveal answer

Answer

In order to find the diagonal, we must know the sides of the rectangle or know whether the triangles ADC or ABD have special angles.

Statement 1 alone doesn't let us calculate the hypothenuse of the triangles, because we only know one side.

Statement 2 alone is sufficient because it allows us to find all angles of the triangles inside of the rectangle. We can see that they are special triangles with angles 30-60-90. Any triangle with these angles will have its sides in ratio , where is a constant. Here, , knowing this, we can calculate the length of the hypothenuse, also the diagonal, which will be .

Hence, statement 2 is sufficient.

← Didn't Know|Knew It →