SAT Math : SAT Mathematics

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #1 : How To Find The Fractional Equivalent Of A Decimal

Convert the decimal to fraction form and reduce it to its simplest form. 

\displaystyle 0.825

Possible Answers:

\displaystyle \frac{165}{200}

\displaystyle \frac{13}{25}

\displaystyle \frac{21}{55}

\displaystyle \frac{825}{1000}

\displaystyle \frac{33}{40}

Correct answer:

\displaystyle \frac{33}{40}

Explanation:

In order to convert \displaystyle 0.825 to a fraction, you would first begin with \displaystyle \frac{825}{1000}, because the decimal literally reads \displaystyle 825 thousandths. You can reduce by \displaystyle 5 a few times or just begin by dividing both numbers by \displaystyle 25 to get \displaystyle \frac{33}{40}.

\displaystyle \frac{825}{1000}=\frac{165}{200}=\frac{33}{40}

Example Question #1251 : Sat Mathematics

If all real values of x\displaystyle x lie between 0 and 1, which of the following is always greater than 1?

Possible Answers:

\frac{x}{10}\displaystyle \frac{x}{10}

x^{4}\displaystyle x^{4}

5x^{2}\displaystyle 5x^{2}

x^{2}\displaystyle x^{2}

x+1\displaystyle x+1

Correct answer:

x+1\displaystyle x+1

Explanation:

If x\displaystyle x is greater than 0, then adding 1 to x\displaystyle x will make it greater than 1. Taking a number between 0 and 1 to a power results in a smaller number.

Example Question #1252 : Sat Mathematics

Evaluate:

0.082

Possible Answers:

0.64

0.064

0.00064

0.0064

0.00064

Correct answer:

0.0064

Explanation:

0.08 * 0.08

First square 8:

8 * 8 = 64

Then move the decimal four places to the left:

0.0064

Example Question #961 : Gre Quantitative Reasoning

Find the square root of the following decimal:

\displaystyle \sqrt{.00081}=

Possible Answers:

\displaystyle 0.009

\displaystyle 90

\displaystyle 0.09

\displaystyle 0.9

\displaystyle 0.028

Correct answer:

\displaystyle 0.028

Explanation:

The easiest way to find the square root of a fraction is to convert it into scientific notation. 

\dpi{100} \small .00081 = 8.1 \times 10^{-4}

The key is that the exponent in scientific notation has to be even for a square root because the square root of an exponent is diving it by two. The square root of 9 is 3, so the square root of 8.1 is a little bit less than 3, around 2.8

 \dpi{100} \small \sqrt{8.1 \times 10^{-4}} \approx 2.8 \times 10^{-2} \approx 0.028

Example Question #1 : How To Find The Square Root Of A Decimal

Find the square root of the following decimal:

\displaystyle \small \sqrt{0.0049}

Possible Answers:

\displaystyle \small 0.022

\displaystyle \small 0.7

\displaystyle \small 0.007

\displaystyle \small 0.07

Correct answer:

\displaystyle \small 0.07

Explanation:

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

\displaystyle \small 0.0049 = 49 \cdot10^{-4}

Because \displaystyle \small 10^{-4} has an even exponent, we can divide the exponenet by 2 to get its square root.

\displaystyle \small \sqrt{0.0049} = \sqrt{49}\cdot\sqrt{10^{-4}} = 7\cdot10^{-2} = 0.07

Example Question #3 : Basic Squaring / Square Roots

Find the square root of the following decimal:

\displaystyle \small \sqrt{0.025}

Possible Answers:

\displaystyle \small 0.05

\displaystyle \small 0.625

\displaystyle \small 0.158

\displaystyle \small 0.005

Correct answer:

\displaystyle \small 0.158

Explanation:

This problem can be solve more easily by rewriting the decimal into scientific notation.

\displaystyle \small 0.025 = 2.5 \times 10^{-2}

Because \displaystyle \small 10^{-2} has an even exponent, we can take the square root of it by dividing it by 2. The square root of 4 is 2, and the square root of 1 is 1, so the square root of 2.5 is less than 2 and greater than 1.

\displaystyle \small \sqrt{0.025} = \sqrt{2.5}\times \sqrt{10^{-2}} = 1.58\times 10^{-1} = 0.158

Example Question #3 : Basic Squaring / Square Roots

Find the square root of the following decimal:

\displaystyle \small \sqrt{0.00036}

Possible Answers:

\displaystyle \small 0.019

\displaystyle \small 0.06

\displaystyle \small 0.013

\displaystyle \small 0.006

Correct answer:

\displaystyle \small 0.019

Explanation:

This problem becomes much simpler if we rewrite the decimal in scientific notation

\displaystyle \small 0.00036 = 3.6\times 10^{-4}

Because \displaystyle \small 10^{-4} has an even exponent, we can take its square root by dividing it by two. The square root of 4 is 2, and because 3.6 is a little smaller than 4, its square root is a little smaller than 2, around 1.9

\displaystyle \small \sqrt{0.025} = \sqrt{3.6}\times \sqrt{10^{-4}} \approx 1.9\times 10^{-2} = 0.019

Example Question #271 : Arithmetic

Find the square root of the following decimal:

\displaystyle \small \sqrt{0.00064}

Possible Answers:

\displaystyle \small 0.8

\displaystyle \small 0.008

\displaystyle \small 0.0253

\displaystyle \small 0.08

Correct answer:

\displaystyle \small 0.0253

Explanation:

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

\displaystyle \small \small 0.00064 = 6.4 \times10^{-4}

Because \displaystyle \small 10^{-4} has an even exponent, we can divide the exponenet by 2 to get its square root. The square root of 9 is 3, and the square root of 4 is two, so the square root of 6.4 is between 3 and 2, around 2.53

\displaystyle \small \small \sqrt{0.00064} = \sqrt{6.4}\times\sqrt{10^{-4}} \approx 2.53 \times10^{-2} = 0.0253

Example Question #1 : How To Find The Square Root Of A Decimal

Find the square root of the following decimal:

\displaystyle \small \sqrt{0.0169}

Possible Answers:

\displaystyle \small 0.0285

\displaystyle \small 0.0411

\displaystyle \small \small 0.0318

\displaystyle \small 0.13

Correct answer:

\displaystyle \small 0.13

Explanation:

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

\displaystyle \small \small 0.0169 = 169\times10^{-4}

Because \displaystyle \small 10^{-4} has an even exponent, we can divide the exponenet by 2 to get its square root. \displaystyle \small 169 is a perfect square, whose square root is \displaystyle \small 13.

\displaystyle \small \small \sqrt{0.0169} = \sqrt{169}\times \sqrt{10^{-4}} =13\times10^{-2} = 0.13

Example Question #5 : How To Find The Square Root Of A Decimal

Find the square root of the following decimal:

\displaystyle \small \sqrt{0.00001}

Possible Answers:

\displaystyle \small 0.01

\displaystyle \small 0.00316

\displaystyle \small 0.0001

\displaystyle \small 0.001

Correct answer:

\displaystyle \small 0.00316

Explanation:

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

\displaystyle \small \small \small 0.00001 = 10 \times10^{-6}

Because \displaystyle \small \small 10^{-6} has an even exponent, we can divide the exponenet by 2 to get its square root. The square root of 9 is 3, so the square root of 10 should be a little larger than 3, around 3.16

\displaystyle \small \small \sqrt{0.00001} = \sqrt{10}\times \sqrt{10^{-6}} = 3.16\times10^{-3} = 0.00316

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