Finding the Third Proportional to 287,230 and 402,490

Step by Step Solution

1. Step 1: Write the proportion equation
   287,230 : 402,490 = 402,490 : x
2. Step 2: Convert to fraction form
   287,230/402,490 = 402,490/x
3. Step 3: Cross multiply
   287,230x = 402,490 × 402,490
4. Step 4: Simplify right side
   287,230x = 161,998,200,100
5. Step 5: Solve for x
   x = 161,998,200,100/287,230
6. Step 6: Final answer
   x = 564,001.67