Finding the Fourth Proportional to 1,128.58, 1,691.34 and 434.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.58 : 1,691.34 = 434.59 : x
2. Step 2: Convert to fraction form
   1,128.58/1,691.34 = 434.59/x
3. Step 3: Cross multiply
   1,128.58x = 1,691.34 × 434.59
4. Step 4: Simplify right side
   1,128.58x = 735,039.45
5. Step 5: Solve for x
   x = 735,039.45/1,128.58
6. Step 6: Final answer
   x = 651.30