Suppose your on a game show and there were three doors. you pick a door then the host opens another door with a goat inside. he asks you if you are going to switch or keep with this door. if you switch, it has a better chance of winning. can anybody explain why?

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.

b

step-by-step explanation: