Finding the Fourth Proportional to 1,070.91, 1,478.52 and 678.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,070.91 : 1,478.52 = 678.60 : x
2. Step 2: Convert to fraction form
   1,070.91/1,478.52 = 678.60/x
3. Step 3: Cross multiply
   1,070.91x = 1,478.52 × 678.60
4. Step 4: Simplify right side
   1,070.91x = 1,003,323.67
5. Step 5: Solve for x
   x = 1,003,323.67/1,070.91
6. Step 6: Final answer
   x = 936.89