Finding the Third Proportional to 256,209 and 407,123.25

Step by Step Solution

1. Step 1: Write the proportion equation
   256,209 : 407,123.25 = 407,123.25 : x
2. Step 2: Convert to fraction form
   256,209/407,123.25 = 407,123.25/x
3. Step 3: Cross multiply
   256,209x = 407,123.25 × 407,123.25
4. Step 4: Simplify right side
   256,209x = 165,749,340,690.56
5. Step 5: Solve for x
   x = 165,749,340,690.56/256,209
6. Step 6: Final answer
   x = 646,930.20