Finding the Fourth Proportional to 1,538.68, 2,123.37 and 840.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,538.68 : 2,123.37 = 840.05 : x
2. Step 2: Convert to fraction form
   1,538.68/2,123.37 = 840.05/x
3. Step 3: Cross multiply
   1,538.68x = 2,123.37 × 840.05
4. Step 4: Simplify right side
   1,538.68x = 1,783,736.97
5. Step 5: Solve for x
   x = 1,783,736.97/1,538.68
6. Step 6: Final answer
   x = 1,159.26