A es ip. a la raiz de B. Cuando A disminuye en 20 unidades, B varia en 7/9 de su valor. hallar 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.

step-by-step explanation:

idk what the heck he answer is, i’m just putting this here so i finish my account