Finding the Third Proportional to 421,288 and 646,012.50

Step by Step Solution

1. Step 1: Write the proportion equation
   421,288 : 646,012.50 = 646,012.50 : x
2. Step 2: Convert to fraction form
   421,288/646,012.50 = 646,012.50/x
3. Step 3: Cross multiply
   421,288x = 646,012.50 × 646,012.50
4. Step 4: Simplify right side
   421,288x = 417,332,150,156.25
5. Step 5: Solve for x
   x = 417,332,150,156.25/421,288
6. Step 6: Final answer
   x = 990,610.11