5 and 6 are true but 7 is not true. If you divide an odd number by 2 it's not going to be half of it
Anything over 90 and bellow 180 degrees is a obtuse.
A few ways. you can enter it into a calculator for one, but the easiest way would be to reference a unit circle and look for an ordered pair where sin (the y value), is equal to -1/2
on a unit circle, the sin value is -1/2 at 7pi/6 and 11pi/6
because sin is the y value, it will additionally be in the quadrants III or IV based on the fact that (-1/2) as a sin value IS a negative and would have to be found in a quadrant in which sin is negative (the lower half of a coordinate plane, in this case)
Answer: 2048 ft
Step-by-step explanation:
Given
The length of each sidewalk is 
There are eight sections of the sidewalk
The total length of the sidewalk is 

Total length of the entire sidewalk is 2048 ft