Finding the Fourth Proportional to 1,399.87, 1,931.34 and 840.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.87 : 1,931.34 = 840.52 : x
2. Step 2: Convert to fraction form
   1,399.87/1,931.34 = 840.52/x
3. Step 3: Cross multiply
   1,399.87x = 1,931.34 × 840.52
4. Step 4: Simplify right side
   1,399.87x = 1,623,329.90
5. Step 5: Solve for x
   x = 1,623,329.90/1,399.87
6. Step 6: Final answer
   x = 1,159.63