A rectangle has dimensions 13 units by 9 units. How many square units are in its area?

Introduction / Context:
This question tests the most basic area formula for a rectangle. Area measures how many unit squares cover the rectangle without gaps or overlaps. When a rectangle has side lengths in units, its area in square units is simply the product of length and breadth. The wording “13 by 9” indicates two perpendicular sides of 13 units and 9 units. Multiplying these gives the number of square units inside the rectangle. This is a direct substitution problem with no conversions, so accuracy comes from using the correct formula and correct multiplication.

Given Data / Assumptions:

• Length = 13 units
• Breadth = 9 units
• Area of rectangle = length * breadth

Concept / Approach:
Use the rectangle area formula: A = L*B. Substitute 13 and 9 and compute the product to get the area in square units.

Step-by-Step Solution:
A = L * B A = 13 * 9 A = 117 square units

Verification / Alternative check:
Think of 13 columns of unit squares and 9 rows of unit squares. Total unit squares = 13*9, which confirms 117.

Why Other Options Are Wrong:
13 and 9 are side lengths, not area. 13/9 is a ratio, not area. 22 is unrelated and could come from adding sides (13+9).

Common Pitfalls:
Adding side lengths instead of multiplying, confusing perimeter with area, or forgetting that area is measured in square units, not units.

Final Answer:
The area is 117 square units.