9514 1404 393
Answer:
20.0 square units
Step-by-step explanation:
There are many ways the area can be computed here. Perhaps the intended one is to find the length of the third side, then use the usual triangle area formula.
b = √(c² -a²) = √(9² -7²) = √32 ≈ 5.7
Then the area is ...
A = 1/2bh = 1/2(5.7)(7) ≈ 20.0
The area is approximately 20.0 square units.
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Additional comment
It is highly unusual to make use of rounded intermediate results. That is a guarantee that the final answer will have more error than necessary. Ordinarily, you would never do that.
An alternate solution might be ...
angle = arccos(7/9) ≈ 38.9°
area = 1/2(7)(9)sin(38.9°) ≈ 19.8 . . . . square units (assuming the sine value is not rounded to 0.6)
