Answer:
DCB=33
Explanation:
We are given the angle for a and we know the angle for ADC is 90 because AB & DC are perpendicular. Given two angles of a triangle we can find the third by subtracting the two known values from 180 because we know a triangle totals 180.
180-33-90=57
So we can also find CDB because we know AB & DC are perpendicular. It is also 90 because two perpendicular lines make a 90 angle.
DCB can be found because we know that ACB makes a 90 angle and the ACD portion is 57. So we subtract 57 from 90.
90-57=33
We can also find CBD by subtracting CDB and DCB from 180.
180-90-33=57
More than question asked but wanted to help you see connections between them.