Difficulty: Easy
Correct Answer: 5 cm
Explanation:
Introduction / Context:This question checks the basic area relationship of a rectangle: Area = length * width. When area and one dimension are known, the other dimension is found by division: width = area / length. Since the units are in centimetres and square centimetres, the division returns a value in centimetres. This is a direct single-formula substitution problem, but accuracy depends on not mixing up which number to divide by and not confusing perimeter with area.
Given Data / Assumptions:
Concept / Approach:Rearrange the rectangle area formula: width = Area / length. Substitute the given values and compute the division.
Step-by-Step Solution: Area = length * width 80 = 16 * width width = 80 / 16 width = 5 cm
Verification / Alternative check:Multiply back to confirm: 16 * 5 = 80 sq cm, which matches the given area. This quick check ensures no division mistake was made.
Why Other Options Are Wrong: 10 cm would give area 16*10=160, too large. 15 cm and 20 cm produce even larger areas. 8 cm gives 128, which does not match 80.
Common Pitfalls:Dividing by the wrong number, writing width = length/area, or mixing units (cm vs mm).
Final Answer:The width of the rectangle is 5 cm.
Discussion & Comments