# What is the slope of the line perpendicular to  y=-3/7x+4 ?

Feb 5, 2016

$s l o p e = \frac{7}{3}$

#### Explanation:

If 2 lines are perpendicular to each other then the product of their gradients is -1 .

let the gradients of the 2 lines be ${m}_{1} \textcolor{b l a c k}{\text{ and }} {m}_{2}$

then ${m}_{1} \times {m}_{2} = - 1 \ldots \ldots \ldots \ldots \left(\cdot\right)$

the equation $y = - \frac{3}{7} x + 4$
is of the form y = mx + c where m represents the gradient and c , the y-intercept.

so ${m}_{1} = - \frac{3}{7} \textcolor{b l a c k}{\text{ and require to find }} {m}_{2}$

using equation (*) : $- \frac{3}{7} \times {m}_{2} = - 1 \textcolor{b l a c k}{\text{ then }} {m}_{2} = - \frac{1}{- \frac{3}{7}}$

slope of perpendicular is $- 1 \times - \frac{7}{3} = \frac{7}{3}$