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
Slot method
8 optionns n 1st slot
7 options in 2nd slot (since 1 is at 1st slot)
6 options in 3rd slot
5 options in 4th slot
8*7*6*5=1680 ways
As we are given with

we are supposed to simplify this expression. which can be done as below


<span>2.1e-10
= 2.1 x 10^-10
= 0.00000000021
hope it helps</span>