Finding the Third Proportional to 687.75 and 1,030.31

Step by Step Solution

1. Step 1: Write the proportion equation
   687.75 : 1,030.31 = 1,030.31 : x
2. Step 2: Convert to fraction form
   687.75/1,030.31 = 1,030.31/x
3. Step 3: Cross multiply
   687.75x = 1,030.31 × 1,030.31
4. Step 4: Simplify right side
   687.75x = 1,061,543.85
5. Step 5: Solve for x
   x = 1,061,543.85/687.75
6. Step 6: Final answer
   x = 1,543.50