Finding the Fourth Proportional to 1,978.16, 2,729.59 and 1,138.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.16 : 2,729.59 = 1,138.80 : x
2. Step 2: Convert to fraction form
   1,978.16/2,729.59 = 1,138.80/x
3. Step 3: Cross multiply
   1,978.16x = 2,729.59 × 1,138.80
4. Step 4: Simplify right side
   1,978.16x = 3,108,457.09
5. Step 5: Solve for x
   x = 3,108,457.09/1,978.16
6. Step 6: Final answer
   x = 1,571.39