Finding the Fourth Proportional to 1,778.79, 2,455.56 and 1,189.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,778.79 : 2,455.56 = 1,189.71 : x
2. Step 2: Convert to fraction form
   1,778.79/2,455.56 = 1,189.71/x
3. Step 3: Cross multiply
   1,778.79x = 2,455.56 × 1,189.71
4. Step 4: Simplify right side
   1,778.79x = 2,921,404.29
5. Step 5: Solve for x
   x = 2,921,404.29/1,778.79
6. Step 6: Final answer
   x = 1,642.35