Question

If the two lines below are perpendicular and the slope ofthe red line is -, what is the slope of the green line?51015-5-5-105

Answer 1

If two lines are perpendicular, then the product of their slopes is -1:

$m_r\cdot m_g=-1...(1)$

From the problem, we identify:

$m_r=-\frac{4}{3}\text{ \lparen the slope of the red line\rparen}$

Then, using the equation (1), we calculate the slope of the green line:

$\begin{gathered} -\frac{4}{3}\cdot m_g=-1 \\ \\ \therefore m_g=\frac{3}{4} \end{gathered}$

Answer: Option D