Answer: 30 yd²
Explanation:
Let's start by flipping the triangle over to become a standard right-angled triangle so that the side measuring 5 yards becomes the bottom and 12 yards becomes the height.
The area of any triangle is
Area = 1/2 x breadth x height
Area = 1/2 x 5yd x 12yd = 5 x 12/2 = 60/2 = 30yd²