(0.5) square meters.
Question 2: Draw the largest circle in a square with an area of 36 square centimeters. The area of this circle is (28.26) square centimeters. Draw the largest square in this circle with an area of (18) square centimeters.
Question 3: The largest round flower pond is 4m in diameter, and 9-4-4= 1 can be built.
Roses in the circle and chrysanthemums outside the circle are the areas left after removing the circle area and rectangle.
Area of circle (area of Chinese rose): 2*2*π= 12.56, two 12.56*2=25. 12 (square meter).
Remaining area (chrysanthemum area): 9*4-25. 12= 10.88 (square meter)
Question 4: 4 in the picture should be the side length. I'll take 4 as the side length. If not, change it.
The area of the shadow part of this problem, cut from the diagonal of the square, can be regarded as a quarter of the area of a circle with a radius of 4, MINUS the area of a high triangle with a base of 4, and then multiplied by 2.
That is, it becomes a semicircle with a radius of 4 minus a square area with a side length of 4.
4*4*π÷2-4*4=9