Finding the Third Proportional to 290,257.50 and 615,780

Step by Step Solution

1. Step 1: Write the proportion equation
   290,257.50 : 615,780 = 615,780 : x
2. Step 2: Convert to fraction form
   290,257.50/615,780 = 615,780/x
3. Step 3: Cross multiply
   290,257.50x = 615,780 × 615,780
4. Step 4: Simplify right side
   290,257.50x = 379,185,008,400
5. Step 5: Solve for x
   x = 379,185,008,400/290,257.50
6. Step 6: Final answer
   x = 1,306,374.54