Finding the Third Proportional to 149,128 and 320,499

Step by Step Solution

1. Step 1: Write the proportion equation
   149,128 : 320,499 = 320,499 : x
2. Step 2: Convert to fraction form
   149,128/320,499 = 320,499/x
3. Step 3: Cross multiply
   149,128x = 320,499 × 320,499
4. Step 4: Simplify right side
   149,128x = 102,719,609,001
5. Step 5: Solve for x
   x = 102,719,609,001/149,128
6. Step 6: Final answer
   x = 688,801.63