Where should a fourth point be located to form a rectangle ?
A) (3, 4)
B) (- 4, 3)
C) (3, - 5)
D) (- 5, 3)

note the y coordinate is negative

Unfortunately this point is not listed as one of the answer choices, but choice A is fairly close. I'm assuming your teacher made a typo.

See the attached image below to see why (3, -4) is the answer.

The idea is you draw horizontal and vertical lines through the given points. One pair of horizontal and vertical lines will intersect at (3, -4) which is the missing corner point. Specifically, the horizontal line through point A(-5,-4) and the vertical line through point C(3,4) intersect to form point D(3,-4).

-2

7 - 9 = -2

reversed:

-2 + 9 = 7

step-by-step explanation:

hans did not square the 40-unit side; he merely multiplied it by 2.   incorrect.