Finding the Fourth Proportional to 1,128.59, 1,692.58 and 765.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.59 : 1,692.58 = 765.61 : x
2. Step 2: Convert to fraction form
   1,128.59/1,692.58 = 765.61/x
3. Step 3: Cross multiply
   1,128.59x = 1,692.58 × 765.61
4. Step 4: Simplify right side
   1,128.59x = 1,295,856.17
5. Step 5: Solve for x
   x = 1,295,856.17/1,128.59
6. Step 6: Final answer
   x = 1,148.21