Finding the Fourth Proportional to 1,393.78, 2,091.70 and 1,123.14

Step by Step Solution

1. Step 1: Write the proportion equation
   1,393.78 : 2,091.70 = 1,123.14 : x
2. Step 2: Convert to fraction form
   1,393.78/2,091.70 = 1,123.14/x
3. Step 3: Cross multiply
   1,393.78x = 2,091.70 × 1,123.14
4. Step 4: Simplify right side
   1,393.78x = 2,349,271.94
5. Step 5: Solve for x
   x = 2,349,271.94/1,393.78
6. Step 6: Final answer
   x = 1,685.54