The slope of the side of ΔABC that is perpendicular to the side EF is 
Response:
- The equation of the side of ΔABC that is perpendicular to EF in slope and intercept form is; <u>y = x + 1</u>
<h3>Which is the method used to find the equation of the perpendicular lines?</h3>
Given:
Points on ΔABC are; A(4, 2), B(4, 5), C(1, 2)
Points on ΔDEF are; , D(2, (-4)), E(5, (-4)), F(2, -1)
The slope of the side BC is 
Equation of side BC is y - 2 = 1·(x - 1) = x - 1
y = x - 1 + 2 = x + 1
y = x + 1
Slope of the side EF is 
Equation of the side EF is y - (-1) = (-1)·(x - 2)
Which gives;
Equation of EF is; y + 1 = (-1)·(x - 2)
Given that the slope of BC is the negative inverse of the slope of EF, we have;
The line BC is perpendicular to the line EF
- The equation of the side of triangle ABC that is perpendicular to EF which is side BC is; <u>y = x + 1</u>
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