Finding the Fourth Proportional to 2,639.59, 3,960.17 and 790.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,639.59 : 3,960.17 = 790.76 : x
2. Step 2: Convert to fraction form
   2,639.59/3,960.17 = 790.76/x
3. Step 3: Cross multiply
   2,639.59x = 3,960.17 × 790.76
4. Step 4: Simplify right side
   2,639.59x = 3,131,557.39
5. Step 5: Solve for x
   x = 3,131,557.39/2,639.59
6. Step 6: Final answer
   x = 1,186.38