Finding the Fourth Proportional to 1,381.84, 1,905.96 and 916.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.84 : 1,905.96 = 916.72 : x
2. Step 2: Convert to fraction form
   1,381.84/1,905.96 = 916.72/x
3. Step 3: Cross multiply
   1,381.84x = 1,905.96 × 916.72
4. Step 4: Simplify right side
   1,381.84x = 1,747,231.65
5. Step 5: Solve for x
   x = 1,747,231.65/1,381.84
6. Step 6: Final answer
   x = 1,264.42