Answer:
45 degrees
Explanation:
As ABCD is a rhombus, all four sides are congruent. Therefore, angle CBD is equal to angle ABD. Since the sum of the angles in a triangle is 180 degrees, the measure of angle ABD plus the measure of angle ADB plus measure of angle CBD equals 180 degrees. Since angle ABD and angle ADB are congruent and add up to 90 degrees, then each angle is (180-90)/2 = 45 degrees. So the measure of angle CBD is also 45 degrees.