Finding the Fourth Proportional to 1,213.76, 1,823.24 and 869.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,213.76 : 1,823.24 = 869.31 : x
2. Step 2: Convert to fraction form
   1,213.76/1,823.24 = 869.31/x
3. Step 3: Cross multiply
   1,213.76x = 1,823.24 × 869.31
4. Step 4: Simplify right side
   1,213.76x = 1,584,956.42
5. Step 5: Solve for x
   x = 1,584,956.42/1,213.76
6. Step 6: Final answer
   x = 1,305.82