Finding the Third Proportional to 553.31 and 799.78

Step by Step Solution

1. Step 1: Write the proportion equation
   553.31 : 799.78 = 799.78 : x
2. Step 2: Convert to fraction form
   553.31/799.78 = 799.78/x
3. Step 3: Cross multiply
   553.31x = 799.78 × 799.78
4. Step 4: Simplify right side
   553.31x = 639,650.05
5. Step 5: Solve for x
   x = 639,650.05/553.31
6. Step 6: Final answer
   x = 1,156.04