In an isoceles triangle, the 2 bottom angles (in this case is angle bad and bcd) are equal.
Triangle DBA and DBC both have 2 equal angles (a right angle, and the bottom angles - property)
So, their third angle must also be equal to each other (cause 3 add up to 180, and since the sum of the first 2 are equal, the third one must also be.)
-> The top angle of triangle BDC is 38
So, we can find angle acb by taking 38 x 2 = 76.
