Finding the Third Proportional to 311,356 and 491,978

Step by Step Solution

1. Step 1: Write the proportion equation
   311,356 : 491,978 = 491,978 : x
2. Step 2: Convert to fraction form
   311,356/491,978 = 491,978/x
3. Step 3: Cross multiply
   311,356x = 491,978 × 491,978
4. Step 4: Simplify right side
   311,356x = 242,042,352,484
5. Step 5: Solve for x
   x = 242,042,352,484/311,356
6. Step 6: Final answer
   x = 777,381.37