Finding the Third Proportional to 315,788 and 678,424

Step by Step Solution

1. Step 1: Write the proportion equation
   315,788 : 678,424 = 678,424 : x
2. Step 2: Convert to fraction form
   315,788/678,424 = 678,424/x
3. Step 3: Cross multiply
   315,788x = 678,424 × 678,424
4. Step 4: Simplify right side
   315,788x = 460,259,123,776
5. Step 5: Solve for x
   x = 460,259,123,776/315,788
6. Step 6: Final answer
   x = 1,457,494.03