Finding the Fourth Proportional to 1,394.59, 2,091.18 and 778.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,394.59 : 2,091.18 = 778.72 : x
2. Step 2: Convert to fraction form
   1,394.59/2,091.18 = 778.72/x
3. Step 3: Cross multiply
   1,394.59x = 2,091.18 × 778.72
4. Step 4: Simplify right side
   1,394.59x = 1,628,443.69
5. Step 5: Solve for x
   x = 1,628,443.69/1,394.59
6. Step 6: Final answer
   x = 1,167.69