Finding the Fourth Proportional to 1,386.17, 1,913.24 and 855.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.17 : 1,913.24 = 855.82 : x
2. Step 2: Convert to fraction form
   1,386.17/1,913.24 = 855.82/x
3. Step 3: Cross multiply
   1,386.17x = 1,913.24 × 855.82
4. Step 4: Simplify right side
   1,386.17x = 1,637,386.41
5. Step 5: Solve for x
   x = 1,637,386.41/1,386.17
6. Step 6: Final answer
   x = 1,181.23