<em>Greetings from Brasil...</em>
We have 2 conditions:
1 - angles opposed by the vertex - the angles are equal
2 - supplementary angles - the sum of the two angles results in 180
2:
(4X + 15) and (5X + 30) are supplementary angles, so:
(4X + 15) + (5X + 30) = 180
9X = 180 - 15 - 30
9X = 135
<h2>X = 15</h2>
1:
(3Y + 15) and (5X + 30) are angles opposed by the vertex, so they are equal
3Y + 15 = 5X + 30
3Y = 5X + 30 - 15
3Y = 5X + 15 <em>above we have already calculated the value of X</em>
3Y = 5.(15) + 15
3Y = 75 + 15
3Y = 90
Y = 90/3
<h3>Y = 30</h3>
Just did a specific one of these; let's do the general case.
The point nearest the origin is (a,b).
The line from the origin through the point is

The line we seek is perpendicular to this one. We swap the coefficients on x and y, negating one, to get the perpendicular family of lines. We set the constant by plugging in the point (a,b):


That's standard form; let's plug in the numbers:

