The pet palace is replacing its dog training arena with a new arena with dimensions that
are twice as large ? old arena 10ft in ht base 15ft. new arena 20ft in ht base 30ft how much greater is the new arena compare to the old one. answers given (a)450ft²(b) 280ft²(c)225ft²(d) 300ft²

it has to be a.

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.