Finding the Fourth Proportional to 1,216.84, 1,678.72 and 791.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.84 : 1,678.72 = 791.32 : x
2. Step 2: Convert to fraction form
   1,216.84/1,678.72 = 791.32/x
3. Step 3: Cross multiply
   1,216.84x = 1,678.72 × 791.32
4. Step 4: Simplify right side
   1,216.84x = 1,328,404.71
5. Step 5: Solve for x
   x = 1,328,404.71/1,216.84
6. Step 6: Final answer
   x = 1,091.68