Finding the Fourth Proportional to 1,399.56, 1,931.36 and 840.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.56 : 1,931.36 = 840.35 : x
2. Step 2: Convert to fraction form
   1,399.56/1,931.36 = 840.35/x
3. Step 3: Cross multiply
   1,399.56x = 1,931.36 × 840.35
4. Step 4: Simplify right side
   1,399.56x = 1,623,004.52
5. Step 5: Solve for x
   x = 1,623,004.52/1,399.56
6. Step 6: Final answer
   x = 1,159.65