You can split it into two triangles and find the area of both triangles and later add them up.
A = bh/2
Triangle 1:
3*3 = 9
9/2 = 4.5
Triangle 2:
3*3 = 9
9/2 = 4.5
4.5 + 4.5 = 9
Answer: The area of the parallelogram is 9 cm^2
Hope this helps :)
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