Farely Simple Problem.. but dont understand formula

[TryingToPassMath]

Problem: Find the Area of an equilateral Triangle with side 12. (that's how the question was written) then formula to use is A=1/4*sqrt3*s(squared)
I dont understand how to do the sqrt3 in the formula..

Also,

Question: Find the length of a 40 degree arc in a circle with a radius of 4.

Possible Answers:
8pi 8pi/9 16pi/9 9pi/8


thanks very much.

 

[Gene]

sqrt(3)=1.732

The circumfrence of the circle is 2*pi*r. There are 360° in a circle. You want 40° of that so the answer is
(40/360)*2*pi*r