Finding the Fourth Proportional to 1,429.89, 1,972.42 and 840.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.89 : 1,972.42 = 840.31 : x
2. Step 2: Convert to fraction form
   1,429.89/1,972.42 = 840.31/x
3. Step 3: Cross multiply
   1,429.89x = 1,972.42 × 840.31
4. Step 4: Simplify right side
   1,429.89x = 1,657,444.25
5. Step 5: Solve for x
   x = 1,657,444.25/1,429.89
6. Step 6: Final answer
   x = 1,159.14