The real answer is going to be 23.5
A simplified ratio may always be a rate.
123 centimeters into dekameters
0.123
10 centimeters = 1 decimeter
100 decimeters = 1 dekameter
Therefore, 100 centimeters = 10 decimeters = 0.1
23 centimeters = 2.3 decimeters = 0.023
0.1 + 0.023 = 0.123 dam