Question 38934
If the sector has a central angle of 36 degrees, then its area is:{{{(36/360)(pi)r^2}}}, we can write:
{{{(pi)r^2/10 = 8.1(pi)}}} Simplify and solve for the radius, r.
{{{r^2 = 81}}}
{{{r = 9}}}cm.

The arc length will be {{{1/10}}} of the circumference or:
{{{(1/10)2(pi)r}}} Simplify.
{{{2(9)(pi)/10 = (18/10)(pi)}}} = {{{1.8(pi)}}}