Finding the Fourth Proportional to 1,387.09, 1,912.98 and 1,200.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.09 : 1,912.98 = 1,200.52 : x
2. Step 2: Convert to fraction form
   1,387.09/1,912.98 = 1,200.52/x
3. Step 3: Cross multiply
   1,387.09x = 1,912.98 × 1,200.52
4. Step 4: Simplify right side
   1,387.09x = 2,296,570.75
5. Step 5: Solve for x
   x = 2,296,570.75/1,387.09
6. Step 6: Final answer
   x = 1,655.68