Finding the Fourth Proportional to 1,188.61, 1,639.72 and 769.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,188.61 : 1,639.72 = 769.09 : x
2. Step 2: Convert to fraction form
   1,188.61/1,639.72 = 769.09/x
3. Step 3: Cross multiply
   1,188.61x = 1,639.72 × 769.09
4. Step 4: Simplify right side
   1,188.61x = 1,261,101.50
5. Step 5: Solve for x
   x = 1,261,101.50/1,188.61
6. Step 6: Final answer
   x = 1,060.99