Finding the Fourth Proportional to 1,200.78, 1,799.55 and 767.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,200.78 : 1,799.55 = 767.16 : x
2. Step 2: Convert to fraction form
   1,200.78/1,799.55 = 767.16/x
3. Step 3: Cross multiply
   1,200.78x = 1,799.55 × 767.16
4. Step 4: Simplify right side
   1,200.78x = 1,380,542.78
5. Step 5: Solve for x
   x = 1,380,542.78/1,200.78
6. Step 6: Final answer
   x = 1,149.71