Finding the Third Proportional to 256,215 and 407,131.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,215 : 407,131.50 = 407,131.50 : x
2. Step 2: Convert to fraction form
   256,215/407,131.50 = 407,131.50/x
3. Step 3: Cross multiply
   256,215x = 407,131.50 × 407,131.50
4. Step 4: Simplify right side
   256,215x = 165,756,058,292.25
5. Step 5: Solve for x
   x = 165,756,058,292.25/256,215
6. Step 6: Final answer
   x = 646,941.27