Jamesk486 wrote:

The figure above shows the shape of a tunnel entrance. If the curved portion is of a circle and the base of the entrance is 12 feet across, what is the perimeter, in feet, of the curved portion of the entrance'?

(A) 9pi

(B) 12pi

(C) 9pi rt(2)

(D) 18pi

(E) 9pi/rt(2)

so how do you solve this??

The correct question is:

The figure above (in the attachment) shows the shape of a tunnel entrance. If the curved portion is

3/4 of a circle and the base of the entrance is 12 feet across, what is the perimeter, in feet, of the curved portion of the entrance'?

Without the information in red the question cannot be solved. Given that piece of information, it follows that the base is one of the sides of an inscribed square in the circle.

For any circle, there are infinitely many rectangles which can be inscribed in it. In particular, squares are also inscribable in a circle.

All the comments stating that a rectangle inscribed in a circle must be a square are completely wrong!

Also, in an ellipse, infinitely many rectangles and a uniques square having sides parallel to the axes of the ellipse can be inscribed.

Please, check the accuracy of the question before posting.

_________________

PhD in Applied Mathematics

Love GMAT Quant questions and running.