Finding the Fourth Proportional to 1,387.83, 1,916.64 and 1,200.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.83 : 1,916.64 = 1,200.42 : x
2. Step 2: Convert to fraction form
   1,387.83/1,916.64 = 1,200.42/x
3. Step 3: Cross multiply
   1,387.83x = 1,916.64 × 1,200.42
4. Step 4: Simplify right side
   1,387.83x = 2,300,772.99
5. Step 5: Solve for x
   x = 2,300,772.99/1,387.83
6. Step 6: Final answer
   x = 1,657.82