Finding the Fourth Proportional to 1,247.06, 1,719.42 and 780.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,247.06 : 1,719.42 = 780.50 : x
2. Step 2: Convert to fraction form
   1,247.06/1,719.42 = 780.50/x
3. Step 3: Cross multiply
   1,247.06x = 1,719.42 × 780.50
4. Step 4: Simplify right side
   1,247.06x = 1,342,007.31
5. Step 5: Solve for x
   x = 1,342,007.31/1,247.06
6. Step 6: Final answer
   x = 1,076.14