The next figure shows a circle with center O inscribed in a square. Point P is one of four points of tangency. By definition, OP ⊥ AB. Also, notice the following relationships between the circle in the preceding figure and the square in which it is inscribed (r 5 radius): • • • • • Each side of the square is 2r in length. The square’s area is (2r)2, or 4r2. 4 The ratio of the square’s area to that of the inscribed circle is . p The difference between the two areas—the total shaded area—is 4r2 2 pr2. 1.
