Answer:
D 3/4
Explanation:
imagine a circle with its center in point A and going through point C.
the radius of that circle is 50 (AC).
remember, tan of an angle is sin/cos of that angle.
now rotate in our imagination that triangle to the right around point A, so that the side AB becomes the bottom base line.
now you see that 30 = sin(A)×radius = sin(A)×50
and 40 = cos(A)×radius = cos(A)×50
so, tan(A) = (sin(A)×50)/(cos(A)×50) = sin(A)/cos(A) = 30/40
= 3/4