Finding the Fourth Proportional to 1,389.24, 1,916.96 and 892.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.24 : 1,916.96 = 892.55 : x
2. Step 2: Convert to fraction form
   1,389.24/1,916.96 = 892.55/x
3. Step 3: Cross multiply
   1,389.24x = 1,916.96 × 892.55
4. Step 4: Simplify right side
   1,389.24x = 1,710,989.67
5. Step 5: Solve for x
   x = 1,710,989.67/1,389.24
6. Step 6: Final answer
   x = 1,231.60