Finding the Fourth Proportional to 1,407.78, 1,942.86 and 786.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.78 : 1,942.86 = 786.78 : x
2. Step 2: Convert to fraction form
   1,407.78/1,942.86 = 786.78/x
3. Step 3: Cross multiply
   1,407.78x = 1,942.86 × 786.78
4. Step 4: Simplify right side
   1,407.78x = 1,528,603.39
5. Step 5: Solve for x
   x = 1,528,603.39/1,407.78
6. Step 6: Final answer
   x = 1,085.83