Since we are to express the given conditions as a joint variation, we employ the use of k as our constant proportionality which we will denote in this item as k.
From the sentence,
F = kM₁M₂/d²
as we can see those in the denominator as those that vary inversely to the given parameter.
Two lines are parallel if they have the same slope. Computing for the slope of line segment ab and line segment cd using m=(y2-y1)/x2-x1):
m of ab=(2-1)/(2-1)=1 m of cd=<span>(4-3)/(4-3)=1
Since line segment ab and line segment cd have the same slope which is 1, then they are said to be parallel. </span>