Multiple choice general knowledge math & puzzles

You can show that (2 + (the square root of 5))^2 = 9 + 4 * (the square root of 5). So my final question is this: What is the square root of (9 + 4 * (the square root of 5)) ?

  1. 2 + (the square root of 5)

  2. 9 + 2 * (the square root of 5)

  3. 3 + 2 * (the square root of 5)

  4. 3 + (the square root of 5)

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The question gives us (2 + √5)² = 9 + 4√5 and asks for √(9 + 4√5). Since we're taking the square root of a perfect square, we get back the original expression: √(9 + 4√5) = 2 + √5. This is a reverse operation question.