Draw the largest circle in a square. What is the ratio of the area of the circle to that of the square

Draw the largest circle in a square. What is the ratio of the area of the circle to that of the square

The area of the garden is 5 * 5 * 3.14159
The square is 10 * 10
That is, 0.5 * 0.5 * 3.14159 = 3.14159/4