Is -451 in the sequence below?
15,7,-1,-9,,-17..

No, the closest to -451 in the sequence is -429

Step-by-step explanation:

nope

Step-by-step explanation:

45.3592

step-by-step explanation:

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.