1.5/2x 1/3=5/6 The circular vertebra is regarded as a cylinder, the cuboid and the cylinder are equal in volume, and the height is inversely proportional to the bottom area. According to equal volume and equal bottom, the height of the cone is three times that of the cylinder.

2。 No picture, no answer.

3。 Volume = cylinder volume-hole volume of middle cuboid

3. 14X(6/2)*(2/6)* 10-2 * 2 * 10

Surface area = side area+upper and lower bottom areas-two square holes+inner cube wall.

3. 14x6x 10+3. 14X(6/2)X(2/6)X2-2x2x 2+2x2x 4

Because it is not convenient to write the square of radius, it is written as radius multiplied by gap diameter. As a result, you do the math.

4。 15:( 100- 15)=3: 17

5。 (1) 7/9-4/9+(4/1+7/1) =1and 1/3.

(2) it is not easy to write. Multiplication of four negative numbers can be regarded as multiplication of four positive numbers, because negative is positive and negative is positive, which can be written as 1/2*2/3*3/4*4/5, and the score is about 1/5.

(3) There is no simple method. If you calculate it directly, you can get 8 1 by treating it as a positive number.

3. The area ratio is the square of the corresponding side length ratio. That is, the length ratio is 2: 3 and the area ratio is 4: 9.