Finding the Third Proportional to 256,081.50 and 387,643.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,081.50 : 387,643.50 = 387,643.50 : x
2. Step 2: Convert to fraction form
   256,081.50/387,643.50 = 387,643.50/x
3. Step 3: Cross multiply
   256,081.50x = 387,643.50 × 387,643.50
4. Step 4: Simplify right side
   256,081.50x = 150,267,483,092.25
5. Step 5: Solve for x
   x = 150,267,483,092.25/256,081.50
6. Step 6: Final answer
   x = 586,795.54