In the diagram, each of the three identical circles touch the other two. The circumference of each circle is 36. What is the area of the shaded region?
https://gyazo.com/0bb2e632441b774f3d412d086fa55957
I made an equilateral triangle using the centers of the triangle.
Since an equilateral triangle has angles of 60o, each sector part is just \(\frac{1}{6}\) of the circle.
Circumference of each circle = 36 units
Radius = \(\frac{18}{π}\)
Sector areas = \(3 \cdot \frac{1}{6} \cdot (\frac{18}{π})^2 π\)
= \(\frac{1}{2} \cdot \frac{324}{π^2}π\)
= \(\frac{1}{2} \cdot \frac{324}{π}\)
= \(\frac{162}{π}\)
Now the area of the equilateral triangle is:
\(\frac{\sqrt{3}}{4}\cdot (\frac{36}{π})^2\)
= \(\frac{\sqrt{3}}{4} \cdot \frac{1296}{π^2}\)
= \(\frac{1296\sqrt{3}}{4π^2}\)
Which means the area of the shaded region is:
\(\frac{1296\sqrt{3}}{4π^2} - \frac{162}{π}\)
= \(\frac{1296\sqrt{3}}{4π^2} - \frac{162π}{π^2}\)
= \(\frac{1296\sqrt{3}}{4π^2} - \frac{648π}{4π^2}\)
= \(\frac{1296\sqrt{3} - 648π}{4π^2}\)
= \(\frac{4(324\sqrt{3} - 162π)}{4π^2}\)
= \(\frac{324\sqrt{3} - 162π}{π^2}\)
please tell me if I did anything wrong...
LOL
I got something complicated as well... I thought I got it incorrect. i actually got the same answer as you, so nothing's wrong... I think.
lol I was debating whether or not to post that because there was a similar question, however this was asking for area of the shaded region instead of the perimeter of it...
See image below:
Triangle area - cicle sector area * 3 = area in question
sqrt(3)/4 ( 36/ pi)2 - 3 * 1/6 * pi ( 18/pi)2 = shaded (we use 1/6 because the sector of the circle is 60/360 of the circle)
324 sqrt(3) / pi2 - 162 / pi <============ Same answer as LR Way to go Logarhythm!!