Finding the Fourth Proportional to 1,355.78, 1,869.40 and 1,106.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.78 : 1,869.40 = 1,106.30 : x
2. Step 2: Convert to fraction form
   1,355.78/1,869.40 = 1,106.30/x
3. Step 3: Cross multiply
   1,355.78x = 1,869.40 × 1,106.30
4. Step 4: Simplify right side
   1,355.78x = 2,068,117.22
5. Step 5: Solve for x
   x = 2,068,117.22/1,355.78
6. Step 6: Final answer
   x = 1,525.41