The area of a rectangle is 80 sq cm. If its length is 16 cm, what is its width (in cm)?

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:

• Area = 80 sq cm
• Length = 16 cm
• Area formula: Area = length * width

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.