Example 1: A cuboid model, the sum of all sides is 72, and the aspect ratio is 4∶3∶2. What is the volume?
A.72B. 192C. 128D.96
The answer to this question is B, and the sum of all side lengths (length four, width four and height four) is 72, that is, length+width+height =72÷4= 18. It is known that the ratio of length to width is 4: 3: 2, so it is 8 in length, 6 in width, 4 in height and 8× 6× 4 in volume.
Example 2: The length, width and height of a rectangular box are 20cm, 8cm and 2cm respectively. Now, all six sides of the box should be completely wrapped in a piece of paper, and the parts cut from the paper can't be used as supplements. Which of the following may be the size of this paper?
A. length 25 cm, width 17 cm.
C. It is 24 cm long and 2 1 cm wide.