Use pythagoras to find the 3rd length of the triangle:
Square root of 8.5^2-7^2= 4.82 yd
Find the area of the trapezium:
((2+(2+4.82))x7)/2
= 30.87 yd^2
To find the area of the parallelogram you just take away the area of the triangle from the area of the trapezium:
Area of triangle is (4.82x7)/2= 16.87yd^2