Finding the Fourth Proportional to 1,128.27, 1,691.20 and 434.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.27 : 1,691.20 = 434.71 : x
2. Step 2: Convert to fraction form
   1,128.27/1,691.20 = 434.71/x
3. Step 3: Cross multiply
   1,128.27x = 1,691.20 × 434.71
4. Step 4: Simplify right side
   1,128.27x = 735,181.55
5. Step 5: Solve for x
   x = 735,181.55/1,128.27
6. Step 6: Final answer
   x = 651.60