Finding the Fourth Proportional to 1,225.15, 1,691.83 and 783.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,225.15 : 1,691.83 = 783.83 : x
2. Step 2: Convert to fraction form
   1,225.15/1,691.83 = 783.83/x
3. Step 3: Cross multiply
   1,225.15x = 1,691.83 × 783.83
4. Step 4: Simplify right side
   1,225.15x = 1,326,100.60
5. Step 5: Solve for x
   x = 1,326,100.60/1,225.15
6. Step 6: Final answer
   x = 1,082.40