Finding the Fourth Proportional to 1,389.34, 1,916.53 and 892.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.34 : 1,916.53 = 892.05 : x
2. Step 2: Convert to fraction form
   1,389.34/1,916.53 = 892.05/x
3. Step 3: Cross multiply
   1,389.34x = 1,916.53 × 892.05
4. Step 4: Simplify right side
   1,389.34x = 1,709,648.89
5. Step 5: Solve for x
   x = 1,709,648.89/1,389.34
6. Step 6: Final answer
   x = 1,230.55