Answer:
(A)
Step-by-step explanation:
Let y be the length of the rectangular backyard and then according to the question, y should be atleast 150 ft, then the possible inequality is:

and the distance around should be no more than 450ft, then the possible inequality is:

Then, the shaded region (green) is the possible dimensions of the backyard.
The height would be 7cm because the area of the base (the triangle face) is 20cm². You would then divide the volume by the area of the base to get the height. 140/20=7cm
Hope this helped!
Step-by-step explanation:
all work is pictured and shown
15 = Juan
12 = Maria
I hope this helps! :D