This is really simple, all you have to do is establish a new relation which describes this particular case;
For example if i wanted to find the area of the full circle (360°), i would use the equation which states that;
[tex]a = \pi \: r {}^{2} [/tex]
[tex]a = \pi \: 8 {}^{2} [/tex]
[tex]a = 3.14 \times 64[/tex]
[tex]a = 201.06 \: inches {}^{2} [/tex]
But do i really wan the full 360 degrees?
In reality i only need a 70 degree circle (in a sense).
If 360 makes a full circle
How many circles is 70?
Use the triple rule to find that;
[tex]x = \frac{70}{360} = 0.1945 \: cirles[/tex]
So that area would be;
[tex] \alpha = 0.1945 \times 201.06 = 39.0617 \: [/tex]
That is your area. a=39 inches² rounded to the nearest tenth.
