Finding the Third Proportional to 287,712 and 431,572.50

Step by Step Solution

1. Step 1: Write the proportion equation
   287,712 : 431,572.50 = 431,572.50 : x
2. Step 2: Convert to fraction form
   287,712/431,572.50 = 431,572.50/x
3. Step 3: Cross multiply
   287,712x = 431,572.50 × 431,572.50
4. Step 4: Simplify right side
   287,712x = 186,254,822,756.25
5. Step 5: Solve for x
   x = 186,254,822,756.25/287,712
6. Step 6: Final answer
   x = 647,365.50