Answer:
7y8.9 ft²
Step-by-step explanation:
Easy way:
Rotate the triangle so that the 12.1 ft side in on the bottom becomes the base.
Drop a line from the top down perpendicular to the 12.1 ft base. That makes a right triangle.
sin 71 = height/13.8
0.9455 = height/13.8
height = 13.05 ft
Area = bh/2 = (12.1)(13.05)(0.5) = 78.9 ft²
