There is a pentagon ABCDE such that angles A, C, and E are all right angles and it is concave at angle C.

If a ray starting at D was aimed at C, it would go exactly 1 inch before going through C, and would eventually go through A.

If BC and AE are both 5 inches, what is the area of this pentagon?

(In reply to C is 90 and concave? by Larry)

Yes it is.  The right angle is just outside the pentagon.  Technically speaking, that's 270 degrees and still a right angle.

Posted by Tristan on 2004-06-12 11:54:16