Finding the Fourth Proportional to 1,429.18, 1,972.34 and 869.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.18 : 1,972.34 = 869.55 : x
2. Step 2: Convert to fraction form
   1,429.18/1,972.34 = 869.55/x
3. Step 3: Cross multiply
   1,429.18x = 1,972.34 × 869.55
4. Step 4: Simplify right side
   1,429.18x = 1,715,043.90
5. Step 5: Solve for x
   x = 1,715,043.90/1,429.18
6. Step 6: Final answer
   x = 1,200.02