Arc length = radius * central angle (measured in radians)
There are
<span>
<span>
<span>
57.2957795131
</span>
</span>
</span>
degrees per radian so
45 degrees = (45 /
<span>
<span>
<span>
57.2957795131) = </span></span></span>
<span>
<span>
<span>
0.7853981634
</span>
</span>
</span>
radians<span><span>
</span>
</span>
radius = arc length / central angle (radians)
radius = 6.5 / <span>
<span>
0.7853981634
</span>
</span>
radians =
<span>
<span>
<span>
8.2760570408
</span>
</span>
</span>
cm
http://www.1728.org/radians.htm
The answer to your question is,
Each time they assume the sum is rational; however, upon rearranging the terms of their equation, they get a contradiction (that an irrational number is equal to a rational number). Since the assumption that the sum of a rational and irrational number is rational leads to a contradiction, the sum must be irrational.
-Mabel <3
8 t ^ 2 + 4 t ^ 2 - 8 4 t
One hundred twenty million five hundred forty thousand<span />
The standard form of a circle is:

Your center is
and your radius is 
Plug them into the equation and you get


The correct answer is D.