# find the angle

• Sep 29th 2007, 09:11 AM
JBswe
find the angle
find the angle for the line

3x-15y+7

do i divid them all by -15 so that i get y alone?

-0.2x+y-0.46

y=-0.2x-0.46

this seems wrong somehow
• Sep 29th 2007, 09:36 AM
red_dog
The line has an equation, not an expression.
$3x-15y+7=0\Rightarrow y=\frac{1}{5}x+\frac{7}{15}$.
The slope is $m=\frac{1}{5}$.
On the other hand, the slope is the tangent of the angle between the line and the positive x-axis.
So, $m=\tan\alpha=\frac{1}{5}\Rightarrow\alpha=\arctan\ frac{1}{5}$.