选择题
2025 AMC 8 Problem 18: Inscribed Square Circles
The circle shown below on the left has a radius of 1 unit. The region between the circle and the inscribed square is shaded. In the circle shown on the right, one quarter of the region between the circle and the inscribed square is shaded. The shaded regions in the two circles have the same area. What is the radius R, in units, of the circle on the right?
2025 AMC 8 第18题：内切方形圆
下面左侧所示的圆的半径为 1 个单位。圆和内切正方形之间的区域是阴影的。在右侧所示的圆圈中，圆圈和内接正方形之间的区域的四分之一是阴影的。两个圆圈中的阴影区域面积相同。右边圆的半径 R（单位）是多少
A.
√2
B.
2
C.
2√2
D.
4
E.
4√2