Finding the Fourth Proportional to 1,191.90, 1,784.78 and 779.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.90 : 1,784.78 = 779.82 : x
2. Step 2: Convert to fraction form
   1,191.90/1,784.78 = 779.82/x
3. Step 3: Cross multiply
   1,191.90x = 1,784.78 × 779.82
4. Step 4: Simplify right side
   1,191.90x = 1,391,807.14
5. Step 5: Solve for x
   x = 1,391,807.14/1,191.90
6. Step 6: Final answer
   x = 1,167.72