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<!DOCTYPE html>
<html data-require="math subhints">
<head>
<title>Square roots 2</title>
<script src="../khan-exercise.js"></script>
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<body>
<div class="summary">Estimating square roots as between two roots
Common Core State Standard: approximately 8.NS
Video coverage: http://www.khanacademy.org/test-prep/cahsee/v/cahsee-practice--problems-1-3 question 2
Prerequisite: Square roots
</div>
<div class="exercise">
<div class="problems">
<div id="square">
<div class="vars">
<var id="N">randRange( 2, 11 )</var>
<var id="Q">randRange( N * N + 1, (N + 1) * (N + 1) - 1 )</var>
</div>
<p class="question">The value of <code>\sqrt{<var>Q</var>}</code> lies between which two <a href="#" class="show-definition" data-definition="consecutive-integers">consecutive integers</a>?</p>
<div class="definition" id="consecutive-integers">
Integers that appear in order when counting, for example 2 and 3.
</div>
<div class="solution" data-type="multiple">
<p><span class="sol short35" data-forms="integer"><var>N</var></span> <code>&lt; \sqrt{<var>Q</var>} &lt;</code> <span class="sol short35" data-forms="integer"><var>N + 1</var></span></p>
<span class="example">two integers, like <code>6</code></span>
</div>
<div class="hints">
<div>
<p>Consider the perfect squares near <code><var>Q</var></code>.
[<a href="#" class="show-subhint"
data-subhint="explain-perfect-square">What are perfect squares?</a>]
</p>
<div class="subhint" id="explain-perfect-square">
<p>
Perfect squares are integers which can be obtained by squaring an integer.
</p>
<p>
The first 13 perfect squares are:
</p>
<code>\qquad 1,4,9,16,25,36,49,64,81,100,121,144,169</code>
</div>
</div>
<p><code><var>N * N</var></code> is the nearest perfect square less than <code><var>Q</var></code>.</p>
<p><code><var>(N + 1) * (N + 1)</var></code> is the nearest perfect square more than <code><var>Q</var></code>.</p>
<p>So, we know <code><var>N * N</var> &lt; <var>Q</var> &lt; <var>(N + 1) * (N + 1)</var></code>.</p>
<p>So, <code>\sqrt{<var>N * N</var>} &lt; \sqrt{<var>Q</var>} &lt; \sqrt{<var>(N + 1)*(N + 1)</var>}</code>.</p>
<p class="final_answer">So <code>\sqrt{<var>Q</var>}</code> is between <code><var>N</var></code> and <code><var>N + 1</var></code>.</p>
</div>
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