Finding the Third Proportional to 387,780 and 820,272

Step by Step Solution

1. Step 1: Write the proportion equation
   387,780 : 820,272 = 820,272 : x
2. Step 2: Convert to fraction form
   387,780/820,272 = 820,272/x
3. Step 3: Cross multiply
   387,780x = 820,272 × 820,272
4. Step 4: Simplify right side
   387,780x = 672,846,153,984
5. Step 5: Solve for x
   x = 672,846,153,984/387,780
6. Step 6: Final answer
   x = 1,735,123.40