From a window 31.0 ft above the street, the angle of elevation to the top of the building across the street is 54.0° and the angle of depression to the base of this
building is 15.0°. Find the height of the building across the street.

y/x of point b= y/x of point a

step-by-step explanation:

(i got the same question, this was the correct answer.)

you need to rotate this triangle about the origin 270 degrees clockwise to create the full square.

proportions are fractions that equal to each other. so if two fractions are the same, they are proportional.

let's check the answers to see if they are proportional.

question a is not proportional because you can't turn 1.5/3 to 3/9. if you try to multiply 1.5/3 by 2 or 3, you wont get 3/9. it's impossible to make the fractions the same.

question b is not proportional because you can't turn 22/33 to 4/6. 33 can't go into 6.

question c is proportional because when you multiply 2 and 3 by 71, you would get 142/213, and those fractions equal to each other

question d is proportional because when you divide 14 and 7 by 2, you would end up with 7/3.5, and those fractions equal to each other.