Quadrilateral ABCD is a square with a side length of 4 cm. A quarter-circle with radius 4 cm and centered at D connects A and C, and a quarter-circle with the same radius centered at B also connects A and C. What is the combined area of both dark regions in the figure at right? Leave your answer in terms of pi.
Hello! I was in a math competition earlier this year and missed this problem. My reasoning: The area of the dark region = Area of square - Unshaded Area Let's call the dark region, d and the unshaded area, u.
d = 16 - [2(PI)(4)^2]/4 --- Because the area of a circle is PI * radius^2 and there are 2
d = 16-8*PI
My answer is incorrect, but can someone show me my error? Thank you.