Let G be some point on the diagonal line away from point E.
Angle DEG represents angle 1.
We're given that angle DEF is a right angle which means it's 90 degrees. Angle DEG is some angle smaller than 90 degrees. By definition, that must mean angle 1 is acute. Any acute angle is smaller than 90 degrees. There's not much else to say other than this is just a definition problem.
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Extra side notes:
If angle 1 was a right angle, then that would mean angle GEF would have to be 0 degrees; however the diagram shows this isn't the case.
If angle 1 was obtuse, then there's no way we'd be able to fit it into angle DEF. In other words, there's no way to have an angle larger than 90 fit in a 90 degree angle.
Answer:
Most likely (B)
Step-by-step explanation:
Points of ABCD:
A (3,1)
B (3,4)
C (5,5)
D (5,2)
The algebraic rule for reflecting across the y axis:
(x,y) ---> (-x, y)
Points of ABCD after being reflected: (shown by figure 2)
A (-3, 1)
B (-3, 4)
C (-5, 5)
D (-5, 2)
Then, the figure got translated two units to the left, resulting in figure F in the picture, and A’B’C’D’ in the question.
Points of ABCD after being translated by (x-2, y) : (shown by figure F)
A (-5, 1)
B (-5, 4)
C (-7, 5)
D (-7, 2)
This should be the coordinates of A’B’C’D’.