You can get 100 points for answering this with well... any answer

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Step-by-step explanation:

tuhu

Thanks

Step-by-step explanation:

Please mark me as brainlist and hit the thanks <3

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.

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