Finding the Fourth Proportional to 1,386.10, 2,081.55 and 978.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.10 : 2,081.55 = 978.10 : x
2. Step 2: Convert to fraction form
   1,386.10/2,081.55 = 978.10/x
3. Step 3: Cross multiply
   1,386.10x = 2,081.55 × 978.10
4. Step 4: Simplify right side
   1,386.10x = 2,035,964.06
5. Step 5: Solve for x
   x = 2,035,964.06/1,386.10
6. Step 6: Final answer
   x = 1,468.84