The value of length y in the given trapezium is equal to 45.66 cm.
Let us start by first naming the trapezium as ABCD.
Now let us construct a line from B perpendicular to CD. Let us call the point touching the line CD as E.
BE ⊥ CD
From this construction, we can say that ED is also 37 cm and BE is 15 cm.
Angle EBC = 125 - 90
Angle EBC = 35 degrees
tan 30 = Perpendicular / base = EC / BE
1 / √3 = EC / 15
EC = 15 / √3 × √3 / √3
EC = 5√3 cm
EC = 8.66 cm
Now let us calculate y:
y = DC + EC
y = 37 + 8.66
y = 45.66 cm