Finding the Fourth Proportional to 1,308.91, 1,806.28 and 778.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,308.91 : 1,806.28 = 778.15 : x
2. Step 2: Convert to fraction form
   1,308.91/1,806.28 = 778.15/x
3. Step 3: Cross multiply
   1,308.91x = 1,806.28 × 778.15
4. Step 4: Simplify right side
   1,308.91x = 1,405,556.78
5. Step 5: Solve for x
   x = 1,405,556.78/1,308.91
6. Step 6: Final answer
   x = 1,073.84