On an aerial photograph, the surface of a pond appears as circular region of 7/16 radius inch. If a distance of 1 inch on the photograph corresponds to an actual distance of 2 miles, which of the following is the closest estimate of the actual surface area of the pond, in square miles?
A. 1.3
B. 2.4
C. 3.0
D. 3.8
E. 5.0
答案给的是B,但是我怎么算出来是A呀, 我的解法是: 3.14*(7/16)^2^2=1.3
这样不对吗? |