5× 1.5=7.5

Question 2

( 1) a-b-c-d-a

(2) A-B-D-C-A

(3) a-d-c-b-a

4) A-C-B-D-A

(5) A-C-D-B

[6] A-DE-B-C-A * * *

Question 3

6×2= 12 9×2= 18 50×2= 100

Question 4

Three eighths, five eighths. Divide a circle into eight points on average. Shadow accounts for 3 parts of the whole circle, white accounts for 5 parts and 8 points, shadow accounts for 3 parts of the whole circle and white accounts for 5 parts.

You can think of six sextants and ten sextants. Divide a circle into sixteen parts, with shadows accounting for six parts of the whole circle and white accounting for ten parts.

Question 5

It should be 176 cubic centimeter.

Idea: Because the remaining part is a cube, the few parts are four faces with the same area, each face is 7 * x.

That is 7*X*4= 1 12, and X=4. Cuboid volume =(4+7)*4*4= 176