The pieces of fabric are already the correct length, so it is just a matter of how many panels will fit into one piece of fabric. 2/(1/2) = 4, so she can make 4 panels from 1 piece of fabric.
When only angles are specified, the sides can be any length, so the triangle is not unique. In any event, the sum of angles must be 180°, so three angles measuring 50° cannot be closed to form a triangle.
Three sides measuring 4, 8, and 14 ft cannot be closed, either, as the long dimension exceeds the sum of the other two. The ends can't meet.
The appropriate choice is the 3rd one ...
... three sides measuring 5 in, 12 in, and 14 in.
The angle on one side of a straight line is 180°, so 40° + 60° + h = 180°.
If you rearrange this you will get h = 180° - 60° - 40°, this will give you: h = 80°.
Hope this helps
Greater than
1/6 x 3/2 = 1/4
1/4 > 1/6