Finding the Fourth Proportional to 1,388.96, 1,914.94 and 1,123.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.96 : 1,914.94 = 1,123.12 : x
2. Step 2: Convert to fraction form
   1,388.96/1,914.94 = 1,123.12/x
3. Step 3: Cross multiply
   1,388.96x = 1,914.94 × 1,123.12
4. Step 4: Simplify right side
   1,388.96x = 2,150,707.41
5. Step 5: Solve for x
   x = 2,150,707.41/1,388.96
6. Step 6: Final answer
   x = 1,548.43