Finding the Fourth Proportional to 1,429.21, 1,972.46 and 839.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.21 : 1,972.46 = 839.74 : x
2. Step 2: Convert to fraction form
   1,429.21/1,972.46 = 839.74/x
3. Step 3: Cross multiply
   1,429.21x = 1,972.46 × 839.74
4. Step 4: Simplify right side
   1,429.21x = 1,656,353.56
5. Step 5: Solve for x
   x = 1,656,353.56/1,429.21
6. Step 6: Final answer
   x = 1,158.93