I believe the answer to this is correct and i believe he did this by adding(i think)
Answer:
a. b=4
Step-by-step explanation:

From the attached triangle drawn below:
NL=20, LM=3b, 

Since we are told that:

The correct option is A.
you would just add both of them together so the weight would be 7.69 Ibs
The answer is D.
The full specification of Newton's First Law is (from Wikipedia)
In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
On earth we're generally in slightly a non-inertial frame, with rotation and revolution around the sun. It's also impossible to turn of gravity, so objects are being acted upon by an outside force. Typically there's also the outside force of friction, which makes things tend to stop.
Rectangular and polar forms are two forms of equations that translates to plot. In this case, the two forms are convertible to each other by the expressions:
r sin theta = y
r cos theta = x
x2 + y2 = r2
we are given the polar expression r csc theta = 8 and is asked to convert to rectangular form.
in this case, csc theta is equal to 1/ sin theta. thys
r / sin theta = 8
in order to make use of the equations above, then
we multiply r to both numerator and denominator in the left side, that is
r^2 / r sin theta = 8
x2+y2 / y = 8
x 2 + y2 = 8y