Gmat club PS.

[bblast]

The area of a square equals that of a circle. Which of the following is closest to the ratio of the diagonal of the square to the diameter of the circle?

0.95
1.26
1.40
1.57
2.51


B







what am I doing wrong ?

area of sq = d^2/2
area of circle = pi r^2

equating we get :
d/r = under root(pi/2) , which is the answer

but we need d/2r so i am getting an additional 1/2 ???

[Frankenstein]

area of sq = d^2/2
area of circle = pi r^2

equating we get :
d/r = under root(pi/2) , which is the answer

You get d/r = under root(2pi)
and d/2r = under root(pi/2)

[bblast]

As always- Thank you Frank.


I will log that down as another silly mistake. Only 2 today but(down from 6-7), lotsa improvement. I wont be harsh on myself.

[MBA.Aspirant]

The area of a square equals that of a circle. Which of the following is closest to the ratio of the diagonal of the square to the diameter of the circle?

1/2 dia^2 = TT d^2/4

2 dia^2 = TT d^2

dia^2/d^2 = TT/2

dia/d = √TT/2

dia/d = 1.25

[mehta003]

I did my answer differently. This is how:

Plugged in Pi for the side of a square and plugged in Sqrt(pi) for the radius of the circle. That way both areas are the same.

When I take the diagonal of the square i would get Pi*Sqrt(2) because of pythagorean theorem. The diameter of the circle is therefore 2*Sqrt(Pi).

Final answer:

Pi:Sqrt(2)


Please let me know if I did anything wrong

[Tani]

Your error is in the last step.

[pi*sqrt(2)]/[2*sqrt(pi) = sqrt(pi)/sqrt(2)