Finding the Fourth Proportional to 1,429.18, 1,972.65 and 839.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.18 : 1,972.65 = 839.90 : x
2. Step 2: Convert to fraction form
   1,429.18/1,972.65 = 839.90/x
3. Step 3: Cross multiply
   1,429.18x = 1,972.65 × 839.90
4. Step 4: Simplify right side
   1,429.18x = 1,656,836.82
5. Step 5: Solve for x
   x = 1,656,836.82/1,429.18
6. Step 6: Final answer
   x = 1,159.29