# Understanding Perimeter, Area, and Volume

Has your child ever struggled with understanding the difference between perimeter, area, and volume?  After all, finding perimeter, area, and volume generally involves using several different formulas depending on the shape you are working with, and that can be extremely confusing for most children.

While children may struggle to choose and work with the correct formula on paper, taking a hands-on approach may help them understand.  Almost any object in your home can be measured for it’s perimeter, area, or volume.

## Perimeter

Perimeter is measuring the distance around an object.  Choose a relatively flat object and have your child measure around it.  They can then add up the sides to find the perimeter.  A circular object (like a clock) would allow your child to practice finding the circumference as well.  To find the circumference, just multiply the diameter (the distance across the center of the circle) times pi (3.14).

## Area

The same objects you used to find perimeter, can be used for finding area as well.  Area formulas change depending on the shape of the object.

• Quadrilaterals (4 sided figures) – multiply the length times the width
• Triangles – multiply the length times the width, then divide by 2
• Circles – multiply the radius times the radius, the multiply that answer by pi (remember the radius is half of the diameter)

## Volume

You can find the volume of any 3D object around your house. (You may want to choose objects that are similar in shape to common prisms and cylinders.)  And remember the formula will change depending on the shape.

• Prisms (shapes with rectangular sides) – find the area of the base shape, then multiply it by the height of the object
• Pyramids (triangular sides that come to a point at the top) – find the area of the base shape, multiply it by the height, then divide by 3
• Cylinders (the shape of a soup can) – find the area of the circular base, then multiply it by the height

Deciding between these formulas can be confusing, but a little hands-on practice at home can make it easier for your child to understand when to use each formula.  You could also use perimeter and area during arts and craft time or to measure their rooms. 