ACT Math : How to find the square root of a decimal

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #11 : How To Find The Square Root Of A Decimal

Evaluate:  

Possible Answers:

Correct answer:

Explanation:

The answer exists because the number inside the radical is not negative.  

First evaluate  by splitting the inside number by its common factor.

The negative sign before the radical means that the negative is distributed after evaluating the radical.

Therefore, the answer is .

Example Question #11 : How To Find The Square Root Of A Decimal

Evaluate:  

Possible Answers:

Correct answer:

Explanation:

The answer does not exist since it's not possible to take the square root of negative numbers.

Example Question #12 : How To Find The Square Root Of A Decimal

Solve for :

Possible Answers:

Correct answer:

Explanation:

Just like any other equation, isolate your variable. Start by multiplying both sides by :

Now, this is the same as:

You know that  is . You can intelligently rewrite this problem as:

, which is the same as:

Example Question #13 : Basic Squaring / Square Roots

Find the square root of the following decimal:

Possible Answers:

Correct answer:

Explanation:

To find the square root of this decimal we convert it into scientific notation.

Because  has an even exponent, we can divide the exponenet by 2 to get its square root.  is a perfect square, whose square root is .

Example Question #1357 : Act Math

If , which of the following is true?

Possible Answers:

Correct answer:

Explanation:

 

 

To convince yourself that  is indeed the square root of , let's square .

 

, so this is true. Since we now know that , the answer that is true given this information is .

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