Well we start with the fundamentals of a triangle we know that all the angles of a triangle add up to 180*, so you can start by adding 55* and 65* and end up with 120* then you can add 30* and get 150* then you can take the total of 150* and subtract it from 180* to get 30 now you take that 30 and divide it by 2 and get 15* for the final angle of the triangle.
If the line is perpendicular to y=5/2X+4, then the line will the the negative reciprocal of the line. The slope of the new line will be -2/5x. Now plugging in the points in the formula should result in the new line being -2/5x-6
