Question

3. Tristan calculated the square root of a number. Then he calculated the square

root of the square root. His answer was 25. What was his original number?
Explain your reasoning.

Answer 1

Answer: His number was 390,625.

Explanation:

We will set up an equation to help us solve. Let x be Tristan's original number.

`\sqrt{√(x) } =25`

Square both sides of the equation:

`√(x) =625`

Square both sides of the equation again:

`x =390,625`

This tells us that Tristan's original number was 390,625.

We can check this result.

Tristan calculated the square root of a number:

`√(390,625) = 625`

Then he calculated the square root of the square root.

`√(625) = 25`

His answer was 25.

`25 = 25` ✓