Finding the Third Proportional to 218,690 and 478,228

Step by Step Solution

1. Step 1: Write the proportion equation
   218,690 : 478,228 = 478,228 : x
2. Step 2: Convert to fraction form
   218,690/478,228 = 478,228/x
3. Step 3: Cross multiply
   218,690x = 478,228 × 478,228
4. Step 4: Simplify right side
   218,690x = 228,702,019,984
5. Step 5: Solve for x
   x = 228,702,019,984/218,690
6. Step 6: Final answer
   x = 1,045,781.79