Finding the Third Proportional to 709.31 and 787.78

Step by Step Solution

1. Step 1: Write the proportion equation
   709.31 : 787.78 = 787.78 : x
2. Step 2: Convert to fraction form
   709.31/787.78 = 787.78/x
3. Step 3: Cross multiply
   709.31x = 787.78 × 787.78
4. Step 4: Simplify right side
   709.31x = 620,599.30
5. Step 5: Solve for x
   x = 620,599.30/709.31
6. Step 6: Final answer
   x = 874.93