Solution:
As per the problem we have
Rectangle JKLM was plotted in the coordinate plane and side segment JK had a slope of 3 fifths.
As we know the sides of the rectangle are always perpendicular to each other.
We also know that when two straight lines are perpendicular to each other then the product of their slopes gives negative one.
[tex] i.e \ \ m_1*m_2=-1\\\ [/tex]
[tex] \frac{3}{5}*m=-1\\
\\
\text{where m=slope of MJ} \\
\\
3m=-5\\
\\
m=\frac{-5}{3} [/tex]
