Look at this shape:

Assume AB = AF = FE = ED and BC = CD, and all the angles in the shape are 90 degrees.

Let A be the area of this shape (in cm^2), and P -- the perimeter of this shape (in cm).

If A - P is 60, what is the length of line AC?

as AB = AF = FE = ED and BC = CD, and all the angles in the shape are 90 degrees,so area=3(x^2)
where x=AB and perimeter=8x.
so eqn is 3x^2-8x-60=0 which gives 6 as x and AC=13.4 by pythagoras theorem.

Posted by abhishek on 2004-03-25 10:47:38