ACT Math : Basic Squaring / Square Roots

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #1 : Square Roots And Operations

x= 100

If x is placed on a number line, what two integers is it between? 

Possible Answers:

4 and 5

5 and 6

3 and 4

Cannot be determined

2 and 3

Correct answer:

3 and 4

Explanation:

It might be a little difficult taking a fourth root of 100 to isolate x by itself; it might be easier to select an integer and take that number to the fourth power. For example 3= 81 and 4= 256. Since 34 is less than 100 and 44 is greater than 100, x would lie between 3 and 4.

Example Question #1 : How To Find A Ratio Of Square Roots

What is the ratio of  to ?

Possible Answers:

Correct answer:

Explanation:

The ratio of two numbers is merely the division of the two values. Therefore, for the information given, we know that the ratio of 

 to 

can be rewritten:

Now, we know that the square root in the denominator can be "distributed" to the numerator and denominator of that fraction:

Thus, we have:

To divide fractions, you multiply by the reciprocal:

Now, since there is one  in , you can rewrite the numerator:

This gives you:

Rationalize the denominator by multiplying both numerator and denominator by :

Let's be careful how we write the numerator so as to make explicit the shared factors:

Now, reduce:

This is the same as 

Example Question #1 : How To Find A Ratio Of Square Roots

 and 

What is the ratio of  to ?

Possible Answers:

Correct answer:

Explanation:

To find a ratio like this, you need to divide  by . Recall that when you have the square root of a fraction, you can "distribute" the square root to the numerator and the denominator. This lets you rewrite  as:

Next, you can write the ratio of the two variables as:

Now, when you divide by a fraction, you can rewrite it as the multiplication by the reciprocal. This gives you:

Simplifying, you get:

You should rationalize the denominator:

This is the same as:

Example Question #1 : Square Roots And Operations

Find the sum:

Possible Answers:

Correct answer:

Explanation:

Find the Sum:

Simplify the radicals:

Example Question #11 : Square Roots And Operations

Add   

Possible Answers:

Correct answer:

Explanation:

The first step when adding square roots is to simplify each term as much as possible. Since the first term has a square within the square root, we can reduce to . Now each term has only prime numbers within the sqaure roots, so nothing can be further simplified and our new expression is .

Only terms that have the same expression within the sqaure root can be combined. In this question, these are the first and third terms. When combining terms, the expression within the square root stays the say, while the terms out front are added. Therefore we get . Since the second term of the original equation cannot be combined with any other term, we get the final answer of .

Example Question #1 : Square Roots And Operations

Simplify: 

 

Possible Answers:

None of the other answers

Correct answer:

Explanation:

Take each fraction separately first:

(2√3)/(√2) = [(2√3)/(√2)] * [(√2)/(√2)] = (2 * √3 * √2)/(√2 * √2) = (2 * √6)/2 = √6

Similarly:

(4√2)/(√3) = [(4√2)/(√3)] * [(√3)/(√3)] = (4√6)/3 = (4/3)√6

Now, add them together:

√6 + (4/3)√6 = (3/3)√6 + (4/3)√6 = (7/3)√6

Example Question #3 : Square Roots And Operations

Simplify the following expression: 

Possible Answers:

Correct answer:

Explanation:

Begin by factoring out each of the radicals:

For the first two radicals, you can factor out a  or :

The other root values cannot be simply broken down. Now, combine the factors with :

This is your simplest form.

Example Question #4 : Square Roots And Operations

Solve for .

Note, :

Possible Answers:

Correct answer:

Explanation:

Begin by getting your  terms onto the left side of the equation and your numeric values onto the right side of the equation:

Next, you can combine your radicals. You do this merely by subtracting their respective coefficients:

Now, square both sides:

Solve by dividing both sides by :

Example Question #12 : Square Roots And Operations

Simplify:

Possible Answers:

Correct answer:

Explanation:

Begin simplifying by breaking apart the square roots in question. Thus, you know:

Now, with square roots, you can combine factors just as if a given root were a variable. So, just as , so too does .

Example Question #13 : Square Roots And Operations

Simplify: .

Possible Answers:

Correct answer:

Explanation:

Begin simplifying by breaking apart the square roots in question. Thus, you know:

Now, with square roots, you can combine factors just as if a given root were a variable. So, just as , so too does 

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