Finding the Third Proportional to 686.50 and 1,054.88

Step by Step Solution

1. Step 1: Write the proportion equation
   686.50 : 1,054.88 = 1,054.88 : x
2. Step 2: Convert to fraction form
   686.50/1,054.88 = 1,054.88/x
3. Step 3: Cross multiply
   686.50x = 1,054.88 × 1,054.88
4. Step 4: Simplify right side
   686.50x = 1,112,761.27
5. Step 5: Solve for x
   x = 1,112,761.27/686.50
6. Step 6: Final answer
   x = 1,620.92