Solving space word problems
This chapter is about space: angles, parallel and perpendicular lines, perimeter, area and volume. In a word problem, first decide which idea the story needs.
Key idea
Understand the question, plan the right rule (perimeter = add all sides, area = length × width, volume = count unit cubes), solve it, then check.
Pick the correct rule
Worked example
A rectangular carpet is 5 m long and 3 m wide. Find the length of tape needed to edge it (perimeter) and the space it covers (area).
Perimeter = 2 × (5 + 3) = 2 × 8 = 16 m. Area = 5 × 3 = 15 m². Check: 5 + 3 + 5 + 3 = 16 m. Correct.
Remember
- Around a shape means perimeter (cm or m).
- Space covered means area (cm² or m²).
- Space filled by a solid means volume (cm³).