Finding the Fourth Proportional to 1,245.77, 1,719.15 and 686.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,245.77 : 1,719.15 = 686.24 : x
2. Step 2: Convert to fraction form
   1,245.77/1,719.15 = 686.24/x
3. Step 3: Cross multiply
   1,245.77x = 1,719.15 × 686.24
4. Step 4: Simplify right side
   1,245.77x = 1,179,749.50
5. Step 5: Solve for x
   x = 1,179,749.50/1,245.77
6. Step 6: Final answer
   x = 947.00