面积:
12*12*3.14/4=113.04
(12+2)*(12+2)*3.14/4=153.86
153.86-113.04=40.82
周长:
12*2*3.14/4=18.84
(12+2)*2*3.14/4=21.98
18.84+21.98+2+2=44.82
面积:
12*12*3.14/4=113.04
(12+2)*(12+2)*3.14/4=153.86
153.86-113.04=40.82
周长:
12*2*3.14/4=18.84
(12+2)*2*3.14/4=21.98
18.84+21.98+2+2=44.82