Finding the Third Proportional to 209,568 and 428,820

Step by Step Solution

1. Step 1: Write the proportion equation
   209,568 : 428,820 = 428,820 : x
2. Step 2: Convert to fraction form
   209,568/428,820 = 428,820/x
3. Step 3: Cross multiply
   209,568x = 428,820 × 428,820
4. Step 4: Simplify right side
   209,568x = 183,886,592,400
5. Step 5: Solve for x
   x = 183,886,592,400/209,568
6. Step 6: Final answer
   x = 877,455.49