Finding the Fourth Proportional to 1,222,400.72, 1,686,828.54 and 678,493.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222,400.72 : 1,686,828.54 = 678,493.76 : x
2. Step 2: Convert to fraction form
   1,222,400.72/1,686,828.54 = 678,493.76/x
3. Step 3: Cross multiply
   1,222,400.72x = 1,686,828.54 × 678,493.76
4. Step 4: Simplify right side
   1,222,400.72x = 1,144,502,638,579.91
5. Step 5: Solve for x
   x = 1,144,502,638,579.91/1,222,400.72
6. Step 6: Final answer
   x = 936,274.51