[Math] How to find area of remaining square with shapes inside

area

enter image description here
Pretty much there is a square with a height and width of $2$", inside there is a perfect circle with radius $1$". Also overlapping the circle and square is a isosceles triangle also with height $2$" and width of the bottom to be $2$". (Truly to see what I'm talking about, you have to click on the image). What is the area of the shaded (gray) region inside of the square not overlapped by the circle or the triangle?

Best Answer

Hint: You know the area of the square and the area of the circle, so the question is the area of the funny shapes in the lower left and right corners. In problems like these, you should look for ways to cut up the shapes into something you know. I added two lines and got this

enter image description here

Now your funny shapes are triangles less the bulge of a circle around the secant. That bulge is the difference between a sector of a circle and a triangle. You need to find the coordinates of the intersection of the circle and the downward lines from the top center of the square. Then find the angle the secant from there to the bottom center represents.