Difficulty: Easy
Correct Answer: 12 cm
Explanation:
Introduction / Context:
This problem focuses on the perimeter of a square. A square is a special rectangle where all four sides are equal. Knowing the side length allows us to find the perimeter easily. This is a fundamental concept in geometry and a common question type in school level aptitude tests.
Given Data / Assumptions:
Concept / Approach:
For a square with side length s, the perimeter P is 4 times the side, because there are four equal sides. Therefore P = 4 * s. The strategy is simply to multiply the given side length by 4 and express the result in centimetres. No further geometric reasoning is required beyond recognising the properties of a square.
Step-by-Step Solution:
Given side s = 3 cm.Perimeter P of a square = 4 * s.So P = 4 * 3 = 12 cm.Therefore the perimeter of the square is 12 centimetres.
Verification / Alternative check:
We can imagine the four sides explicitly: each side is 3 cm, and there are four of them. Adding them directly gives 3 + 3 + 3 + 3 = 12 cm. This confirms the formula based calculation and ensures there is no arithmetic mistake. Both methods yield the same perimeter, which increases confidence in the answer.
Why Other Options Are Wrong:
13 cm, 14 cm, and 15 cm represent values close to the correct answer and could result from adding numbers incorrectly, such as 3 + 4 + 5 or 3 + 3 + 3 + 4. 9 cm might come from multiplying 3 by 3 instead of by 4, confusing area with perimeter. None of these values equal four times the side length, so they do not represent the true perimeter of the square.
Common Pitfalls:
Learners sometimes confuse the formulas for area and perimeter. Area of a square is s^2, whereas perimeter is 4 * s. Mixing them up leads to answers like 9 cm or 9 sq cm in this problem. Remember that perimeter is a linear measure around the boundary, while area covers the interior space. Keeping units in mind also helps: perimeter is in cm, area in sq cm.
Final Answer:
12 cm
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