Finding the Third Proportional to 287,145 and 421,834.50

Step by Step Solution

1. Step 1: Write the proportion equation
   287,145 : 421,834.50 = 421,834.50 : x
2. Step 2: Convert to fraction form
   287,145/421,834.50 = 421,834.50/x
3. Step 3: Cross multiply
   287,145x = 421,834.50 × 421,834.50
4. Step 4: Simplify right side
   287,145x = 177,944,345,390.25
5. Step 5: Solve for x
   x = 177,944,345,390.25/287,145
6. Step 6: Final answer
   x = 619,702.05