From the condition, you have the measure of the angle ABC = two times the measure of the angle ABD. In terms of "x" it means 9x = 2*(4x + 13) 9x = 8x + 26 x = 26 degrees. Then the measure of the angle DBC = 4x + 13 = 4*26 + 13 = 117 degrees. Answer. The measure of the angle DBC is 117 degrees.