Finding the Fourth Proportional to 715.72, 1,064.22 and 686.56

Step by Step Solution

1. Step 1: Write the proportion equation
   715.72 : 1,064.22 = 686.56 : x
2. Step 2: Convert to fraction form
   715.72/1,064.22 = 686.56/x
3. Step 3: Cross multiply
   715.72x = 1,064.22 × 686.56
4. Step 4: Simplify right side
   715.72x = 730,650.88
5. Step 5: Solve for x
   x = 730,650.88/715.72
6. Step 6: Final answer
   x = 1,020.86