We can see a right triangle in this problem,
where a vertical distance is a leg that opposite to the angle 20⁰ , and horizontal distance is an adjacent leg to the 20⁰ angle.
So,
tan (20⁰) = opposite leg/adjacent leg
tan (20⁰) = vertical distance/horizontal distance
tan (20⁰) = 30 /horizontal distance
horizontal distance= 30/tan(20⁰) ≈ 82.4 in.
