Finding the Fourth Proportional to 2,618.58, 3,929.88 and 1,386.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,618.58 : 3,929.88 = 1,386.30 : x
2. Step 2: Convert to fraction form
   2,618.58/3,929.88 = 1,386.30/x
3. Step 3: Cross multiply
   2,618.58x = 3,929.88 × 1,386.30
4. Step 4: Simplify right side
   2,618.58x = 5,447,992.64
5. Step 5: Solve for x
   x = 5,447,992.64/2,618.58
6. Step 6: Final answer
   x = 2,080.51