Finding the Fourth Proportional to 1,245.86, 1,719.27 and 686.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,245.86 : 1,719.27 = 686.39 : x
2. Step 2: Convert to fraction form
   1,245.86/1,719.27 = 686.39/x
3. Step 3: Cross multiply
   1,245.86x = 1,719.27 × 686.39
4. Step 4: Simplify right side
   1,245.86x = 1,180,081.14
5. Step 5: Solve for x
   x = 1,180,081.14/1,245.86
6. Step 6: Final answer
   x = 947.21