1. The problem statement, all variables and given/known data I've pretty much given up on this problem: "A spotlight throws a beam of light that is 25 cm in diameter. If the beam hits the stage floor at an angle of 60 degrees with the horizontal, find an equation for the elliptical pool of light on the stage floor. (Figure 2-23)" http://books.google.com/books?id=4lwuyKlK6FsC&lpg=PA50&ots=cJyn8pzoNu&dq=33&pg=PA50" at Google books. The answer is [tex](x^2/208.3) + (y^2/156.3) = 1 [/tex] (all odd-numbered questions have answers provided in the back). It doesn't show any work, however. 2. Relevant equations The equation for an ellipse: [tex](x^2/a^2) + (y^2/b^2) = 1[/tex] Equation for circle: [tex]x^2 + y^2 = a^2[/tex] Pythagorean Theorem [tex]a^2 = b^2 + c^2[/tex] 3. The attempt at a solution I tried [tex]25*cos (60) = 12.5 [/tex] to attempt to find the length of the y axis above the horizontal. This is correct according to the back of the book as [tex]12.5^2 = 156.25[/tex]. But now I'm stuck.