Finding the Fourth Proportional to 1,128.87, 1,692.15 and 762.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.87 : 1,692.15 = 762.79 : x
2. Step 2: Convert to fraction form
   1,128.87/1,692.15 = 762.79/x
3. Step 3: Cross multiply
   1,128.87x = 1,692.15 × 762.79
4. Step 4: Simplify right side
   1,128.87x = 1,290,755.10
5. Step 5: Solve for x
   x = 1,290,755.10/1,128.87
6. Step 6: Final answer
   x = 1,143.40