Answer: the area is 80 square units
Step-by-step explanation: The diagram is NOT a parallelogram, so I hope the rest of the information given is correct.
The formula for area of a parallelogram is A = ba, or A = bh depending on your system.
b is the base, the length of the top and bottom.
a or h is the altitude or height, the vertical distance between the bases (not the length of the diagonal side.)
Here the base is given as 10, and the altitude is 8. So multiply
A = ba
A = 10 × 8
A = 80 square units.