Finding the Fourth Proportional to 1,309.50, 1,806.72 and 778.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,309.50 : 1,806.72 = 778.16 : x
2. Step 2: Convert to fraction form
   1,309.50/1,806.72 = 778.16/x
3. Step 3: Cross multiply
   1,309.50x = 1,806.72 × 778.16
4. Step 4: Simplify right side
   1,309.50x = 1,405,908.20
5. Step 5: Solve for x
   x = 1,405,908.20/1,309.50
6. Step 6: Final answer
   x = 1,073.62