One way is to first find the measure of one external angle:-
Measure 1 ext angle = 360 / 10 = 36 degrees (Note the sum of the external angles of all polygons is 360 degrees)
So the internal angle = 180 - 36 = 144
So sum of the internal angles
= 10 * 144
= 1440 degrees (answer)
Let's change this question a bit: Find two integers, one just slightly greater than 41/3 and the other just slightly smaller than 41/3.
Rounding 41 up to 42: 42/3 = 14
Rounding 41 down to 39: 39/3 = 13
The quotient lies between 13 and 14, and is closer to 14.
3x+5y=45
X+y=11
3x+3y=33
5y=45-3x
Y=15-3/5x
X+15-3/5x=11
X-3/5x=-4
5x-3x=-20
X=10
Y=1
