Finding the Fourth Proportional to 1,918.55, 2,878.28 and 685.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,918.55 : 2,878.28 = 685.86 : x
2. Step 2: Convert to fraction form
   1,918.55/2,878.28 = 685.86/x
3. Step 3: Cross multiply
   1,918.55x = 2,878.28 × 685.86
4. Step 4: Simplify right side
   1,918.55x = 1,974,093.69
5. Step 5: Solve for x
   x = 1,974,093.69/1,918.55
6. Step 6: Final answer
   x = 1,028.95