Roland made a trip of 450 miles in 8 hrs. before noon he averaged 60 miles per hr, and after noon he averaged 50 miles per hr. at what time did he begin his trip and when did he end? ?

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

1,918

step-by-step explanation: