Answer:
Step 2
Explanation:
Let

Plot the vertices to better understand the problem
see the attached figure
The area of the rectangle is equal to

we have

step 1
Find the base b (BD)

step 1 is correct
step 2
Find the height h (BA)

step 2 is not correct
step 3
Find the area

Therefore
Sara first make a mistake in finding the area of the rectangle in Step 2