Finding the Fourth Proportional to 1,389.83, 1,914.89 and 916.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.83 : 1,914.89 = 916.89 : x
2. Step 2: Convert to fraction form
   1,389.83/1,914.89 = 916.89/x
3. Step 3: Cross multiply
   1,389.83x = 1,914.89 × 916.89
4. Step 4: Simplify right side
   1,389.83x = 1,755,738.91
5. Step 5: Solve for x
   x = 1,755,738.91/1,389.83
6. Step 6: Final answer
   x = 1,263.27