Finding the Fourth Proportional to 1,381.91, 1,907.54 and 916.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.91 : 1,907.54 = 916.31 : x
2. Step 2: Convert to fraction form
   1,381.91/1,907.54 = 916.31/x
3. Step 3: Cross multiply
   1,381.91x = 1,907.54 × 916.31
4. Step 4: Simplify right side
   1,381.91x = 1,747,897.98
5. Step 5: Solve for x
   x = 1,747,897.98/1,381.91
6. Step 6: Final answer
   x = 1,264.84