What is the square root of 121?

Appeared in: RML PRE 2025

Explanation

The square root of a number is a value that, when multiplied by itself, equals the original number.
In this case, 11 multiplied by 11 (11 × 11) equals 121.
Therefore, 11 is the correct square root of 121.

Option B: The square of 112 (112 × 112) is 12,544, which is significantly larger than 121.
Option C: The square of 15 (15 × 15) is 225, not 121.
Option D: The square of 21 (21 × 21) is 441, not 121.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculating the square root of a perfect square as background academic context rather than a clinical decision trigger.
While not a direct clinical skill, basic math proficiency is essential for nurses for accurate medication dosage calculations, setting IV drip rates, and interpreting patient data like intake/output charts.
Errors in calculation can have serious patient safety consequences, making mathematical accuracy a fundamental professional responsibility.
What if? If the question asked for the square of 11, the answer would be 121. It's crucial to differentiate between finding a square root (√x) and squaring a number (x²).

How to Approach the Question

This is a factual recall question from mathematics, a non-nursing subject that can appear in nursing entrance exams.
First, identify the core mathematical operation required: finding the 'square root' of the number 121.
Recall the definition of a square root: a number that, when multiplied by itself, results in the original number.
Systematically test the given options. Multiply each option by itself to see which product equals 121.
Calculation: 11 × 11 = 121. This matches the number in the question, identifying it as the correct answer.
To be certain, quickly check the other options: 15 × 15 = 225 and 21 × 21 = 441, confirming they are incorrect.

Concept Tested & Keywords

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Practise the full RML PRE 2025

Attempt every question from this paper in a timed mock, then review the full solution for each one.