+1776 Triangle ABC has vertices A(2,3), B(1,−8) and C(−3,2). The line containing the altitude through A intersects the point (0,y). What is the value of y?
0 The altitude will have the negative inverse of the slope of ¯BC becasue it is perpedicular. Now with having a pointA on the line and its slope, we know everything about the line therefore:
2−(−8)−3−1=−52
negative inverse=25
using point-slope form:
y−y1=x(x−x1)y−3=x(25−2) <----lets plug in (0,y)y−3=0y=3
