"medium" math question?

<p>I'm drawing a blank, how do u do this math problem. The answer is 108pi</p>

<p>If the length of arc QR is 6pi what is the area of sector PQR, where P is the center? </p>

<p>They also tell u the central angle is 30 but u can get that from changing the 6pi to degress(its question 19 in part 3 of the second practice test in the college board review book)</p>

<p>length of a sector = (n/360) * 2piR</p>

<p>30/360 * (2)(pi)(r) = 6pi</p>

<p>Solving for R gets you r=36 (radius!)</p>

<p>Area of a sector = (n/360) * pi(r^2)</p>

<p>(30/360)*(pi(36^2)) = 108pi</p>

<p>haha thanx, i just got it after i posted it</p>

<p>Find the circumference
72 Pi= C
36= r
Using the radius, find the area of the full circle, which would be 1296 Pi. Now multiply that with 1/12 (30/360) to find the area of only that section of the circle.</p>

<p>The answer will yield to 108 Pi.</p>

<p>Beat me ! Edit</p>