Finding the Third Proportional to 309,100.50 and 490,380.75

Step by Step Solution

1. Step 1: Write the proportion equation
   309,100.50 : 490,380.75 = 490,380.75 : x
2. Step 2: Convert to fraction form
   309,100.50/490,380.75 = 490,380.75/x
3. Step 3: Cross multiply
   309,100.50x = 490,380.75 × 490,380.75
4. Step 4: Simplify right side
   309,100.50x = 240,473,279,970.56
5. Step 5: Solve for x
   x = 240,473,279,970.56/309,100.50
6. Step 6: Final answer
   x = 777,977.65