Finding the Fourth Proportional to 1,105.51, 1,655.76 and 915.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.51 : 1,655.76 = 915.70 : x
2. Step 2: Convert to fraction form
   1,105.51/1,655.76 = 915.70/x
3. Step 3: Cross multiply
   1,105.51x = 1,655.76 × 915.70
4. Step 4: Simplify right side
   1,105.51x = 1,516,179.43
5. Step 5: Solve for x
   x = 1,516,179.43/1,105.51
6. Step 6: Final answer
   x = 1,371.48