Finding the Third Proportional to 256,401 and 561,128.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,401 : 561,128.50 = 561,128.50 : x
2. Step 2: Convert to fraction form
   256,401/561,128.50 = 561,128.50/x
3. Step 3: Cross multiply
   256,401x = 561,128.50 × 561,128.50
4. Step 4: Simplify right side
   256,401x = 314,865,193,512.25
5. Step 5: Solve for x
   x = 314,865,193,512.25/256,401
6. Step 6: Final answer
   x = 1,228,018.59