<?xml version="1.0" encoding="UTF-8"?>
<quiz>
  <question type="description">
    <name>
      <text>6.2.15 (Radius and area)</text>
    </name>
    <questiontext format="moodle_auto_format">
      <text><![CDATA[<h1>Radius and area</h1>

<p>We should all be familiar with the concept of the radius and area of a circle. The idea of this section is to remind you of how to calculate the area of a circle as well as go through some examples relating to these concepts. Recall that if we have a circle of radius \(r\) then its area is given by 
\[
\mbox{Area} = A = \pi r^2.
\]</p>
<br/>
<h3>Example</h3>

<p>Given that the circumference of a circle is \(18\pi\)cm find its area.</p>

<h3>Solution</h3>

<p>Recall that the circumference of a circle is given by \(2\pi r\). Here we have \(36\pi = 2 \pi r\) and so rearranging gives \(r = 9\). The area of a circle is given by \(A = \pi r^2\) and so here we have 
\[
A = \pi \cdot (9)^2 = 81\pi.
\]
</p>]]></text>
    </questiontext>
    <generalfeedback format="moodle_auto_format">
      <text/>
    </generalfeedback>
    <defaultgrade>0</defaultgrade>
    <penalty>0</penalty>
    <hidden>0</hidden>
    <idnumber/>
  </question>
</quiz>
