The important point is that the surface area to the volume ratio gets smaller as the cell gets larger. Thus, if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. That is why cells are so small.

Unit 9 Section 4 : Surface Area and Volume of 3-D Shapes

Volume of a 3-d shape is defined as the total space enclosed/occupied by any 3-dimensional object or solid shape. It also can be defined as the number of unit cubes that can be fit into the shape. The SI unit of volume is cubic meters.

The unit and topics of area and perimeter are important to mathematics because they are the physical aspects of mathematics. Learning about area and perimeter will give the students a chance to use math that real people need and use outside of school.

Use visual cues to differentiate perimeter from area. This is why I try to help students identify ways to differentiate the two. Providing a visual reminder can really make a huge difference in helping students recall the two terms and what they mean.

Some students also confuse the concepts of area and perimeter because they experience difficulty understanding the differences between linear (one-dimensional) units and squared (two-dimensional) units or are unable to connect their everyday experience with area and perimeter to what they learn in the classroom.

Uses of perimeter and area in daily life ​

1. Fencing off an area to plot a crop. Since fences cost money for a given area you would want to minimize the perimeter.
2. Planning the construction of a house.
3. Building a barn with box stalls for horses.
4. Wood.
5. Building a swimming pool.