Finding the Fourth Proportional to 1,387.04, 1,912.89 and 1,200.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.04 : 1,912.89 = 1,200.47 : x
2. Step 2: Convert to fraction form
   1,387.04/1,912.89 = 1,200.47/x
3. Step 3: Cross multiply
   1,387.04x = 1,912.89 × 1,200.47
4. Step 4: Simplify right side
   1,387.04x = 2,296,357.49
5. Step 5: Solve for x
   x = 2,296,357.49/1,387.04
6. Step 6: Final answer
   x = 1,655.59