Math Background

Perimeter, Area, and Volume: When Students Ask

  • What is the perimeter of a figure?
    Perimeter is the distance around a figure. To find the perimeter of a figure, add the lengths of the sides.
  • What does ft² mean?
    The expression ft² means “square feet.” Area is found by multiplying two dimensions, length and width. The result is expressed in square units.
  • If two figures have the same area, will they have the same perimeter?
    Figures with the same area can have different perimeters; and figures with the same perimeter can have different areas.
  • What is the difference between surface area and volume?
    Surface area is the sum of the areas of all the faces of the solid figure. It is measured in square units. Volume is the number of cubic units that make up a solid figure.
  • How can I remember the formulas for finding area and volume?
    Remind students that area is measured in square units and volume is measured in cubic units. Square units are units x units. Cubic units are units x units x units. In the formula for the area of a rectangle, A = l x w, you multiply two dimensions. In the formula for the volume of a rectangular prism, V = l x w x h, you multiply three dimensions.

Houghton Mifflin Math Grade 4