I believe that because there are 180 degrees in a triangle, and ACB is a triangle, you can add up two of the angles and subtract that from 180. So
30+50=80 and 180-80=100, that mean the angle above angle 1 is 100. And since angle one and that angle 100 are vertical angles, angle 1 = 100
Let the cost of one sheep and one cow be x and y respectively.
Therefore,
5x+5y=129
10x+17y =177
Solving the two equations,
Multiply the first equation by 2 and subtract the second from the results;
10x+10y = 258
10x+17y = 177
0x-7y = 81 => y= $-11.57 (cannot be a negative value). The details of the question need to be checked.
Now,
5x+5y = 129 => 5x-57.86 =129=>5x = 186.86 => x= $37.37
Triangle for the sides and the for the bottom of the shape, square
<span>5/6 X 360 = 300 degrees </span>