Finding the Fourth Proportional to 1,071.85, 1,478.91 and 678.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,071.85 : 1,478.91 = 678.73 : x
2. Step 2: Convert to fraction form
   1,071.85/1,478.91 = 678.73/x
3. Step 3: Cross multiply
   1,071.85x = 1,478.91 × 678.73
4. Step 4: Simplify right side
   1,071.85x = 1,003,780.58
5. Step 5: Solve for x
   x = 1,003,780.58/1,071.85
6. Step 6: Final answer
   x = 936.49