Finding the Third Proportional to 777.38 and 1,087.31

Step by Step Solution

1. Step 1: Write the proportion equation
   777.38 : 1,087.31 = 1,087.31 : x
2. Step 2: Convert to fraction form
   777.38/1,087.31 = 1,087.31/x
3. Step 3: Cross multiply
   777.38x = 1,087.31 × 1,087.31
4. Step 4: Simplify right side
   777.38x = 1,182,248.47
5. Step 5: Solve for x
   x = 1,182,248.47/777.38
6. Step 6: Final answer
   x = 1,520.82