Finding the Third Proportional to 256,081.50 and 389,407.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,081.50 : 389,407.50 = 389,407.50 : x
2. Step 2: Convert to fraction form
   256,081.50/389,407.50 = 389,407.50/x
3. Step 3: Cross multiply
   256,081.50x = 389,407.50 × 389,407.50
4. Step 4: Simplify right side
   256,081.50x = 151,638,201,056.25
5. Step 5: Solve for x
   x = 151,638,201,056.25/256,081.50
6. Step 6: Final answer
   x = 592,148.21