Finding the Fourth Proportional to 1,380.56, 1,905.96 and 915.44

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.56 : 1,905.96 = 915.44 : x
2. Step 2: Convert to fraction form
   1,380.56/1,905.96 = 915.44/x
3. Step 3: Cross multiply
   1,380.56x = 1,905.96 × 915.44
4. Step 4: Simplify right side
   1,380.56x = 1,744,792.02
5. Step 5: Solve for x
   x = 1,744,792.02/1,380.56
6. Step 6: Final answer
   x = 1,263.83