Question

第一道还有一个选项是2

Answer 1

1.△AFD ∽△EFB,所以,EF:FA=EB:AD=1:2

也就是说,EF:AE = 1：3

那么,S△EBF = 1/3 * S△ABE

又因为,S△ABE = 1/2 * S△ABC = 1/2 * (1/2 * SABCD) = 1/4 * 36 = 9

所以,S△EBF = 1/3 * 9 = 3

因此,答案是 A

2.T = (S1/4 + S2/3 + S3/6 + S4/4) + (S4/4 + S3/3 + S2/6 + S1/4)

= (S1 + S4)/2 + (S2/3 + S3/3) + (S2/6 + S3/6)

= (S1 + S4)/2 + (S2 + S3)(1/3 + 1/6)

= (S1 + S4)/2 + (S2 + S3)/2

= (S1 + S4 + S2 + S3)/2 = 5

所以,总路程 S = S1+S2+S3+S4 = 10 km