如果立方体的长度增加一倍,它的体积会发生什么变化?
立方体是与一定体积相关联的三维形状。它有六个方形面,每个面对应一个相等的长度。它可以被认为是堆叠在一起的正方形片材。也称为正六面体,是五种柏拉图立体形状之一。
立方体的体积
立方体的体积是占据一定质量或空间体积的三维形状。立方体的体积单位为(单位) 3或立方单位。 SI 的体积单位是立方米 (m 3 )。
使用边长的立方体体积
立方体所有边的度量都是相同的,因此我们只需要知道一个边即可计算立方体的体积。使用边长计算立方体体积的步骤是,
- 第 1 步:记下立方体的边长,比如边。
- 第 2 步:现在,立方体的体积 = (side) 3 。
- 第 3 步:最终答案与立方单位一起测量。
立方体公式的体积
Volume of the cube = Side × Side × Side = Side3
如果立方体的长度增加一倍,它的体积会发生什么变化?
解决方案:
Volume of the cube = Side3
Since,
All the sides of the cube are equal
Then if the length of a side of the cube is increased
So, the side of the cube becomes
Side of the cube = 2 × Side
Assume
Side of the cube be ‘s’
Side of the cube = 2s
Now,
Volume of the cube = 2s × 2s × 2s
Volume of the cube = (2s)3
Volume of the cube = 8s3
To find how many times the volume of the cube is increased
⇒
⇒ 8s3/ s3
⇒ 8
Therefore,
If the length of the cube is doubled then its volume is increased by 8 times.
示例问题
问题1.如果立方体的边减少到一半会发生什么?
解决方案:
As we know that
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Assume the side of the cube be ‘s’
Volume of the cube = s3
According to the question
The side of the cube is decreased to half
Therefore,
Side of the cube = s/2
Now,
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Volume of the decreased side cube = s/2 × s/2 × s/2
Volume of the decreased side cube = (s/2)3
Volume of the decreased side cube = s3/8
Therefore,
If we decrease the side of the cube to half then its volume is decreased by 8 times.
问题2.如果立方体的边增加三倍,立方体的体积会增加多少倍?
解决方案:
As we know that
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Assume the side of the cube be ‘s’
Volume of the cube = s3
According to the question
The side of the cube is increased by 3 times
Therefore,
Side of the cube = 3 × s
Now,
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Volume of the decreased side cube = 3s × 3s × 3s
Volume of the decreased side cube = (3s)3
Volume of the decreased side cube = 27s3
Therefore,
If we increase the side of the cube to 3 times then its volume is increased by 27 times.
问题3.如果立方体的边减少到1/4,计算立方体体积的减少量?
解决方案:
As we know that
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Assume the side of the cube be ‘s’
Volume of the cube = s3
According to the question
The side of the cube is decreased to 1/4
Therefore,
Side of the cube = s/4
Now,
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Volume of the decreased side cube = s/4 × s/4 × s/4
Volume of the decreased side cube = (s/4)3
Volume of the decreased side cube = s3/64
Therefore,
If we decrease the side of the cube by 1/4 then its volume decreases by 64 times.
问题 4. 求一个边长为 8 厘米的大立方体可以拼出多少个边长为 2 厘米的小立方体?
解决方案:
As we know that
Volume of the cube = Side × Side × Side
Volume of the cube = Side3
Volume of small cube = 2 × 2 × 2
Volume of small cube = 8 cm3
Volume of big cube = 8 × 8 × 8
Volume of big cube = 512 cm3
To find how many small cubes can be made out of big cube
⇒
⇒ 512/8
⇒ 64
Therefore,
64 small cubes of side 2 cm can be made out of a big cube of side 8 cm.