Finding the Fourth Proportional to 1,309.11, 1,806.69 and 719.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,309.11 : 1,806.69 = 719.78 : x
2. Step 2: Convert to fraction form
   1,309.11/1,806.69 = 719.78/x
3. Step 3: Cross multiply
   1,309.11x = 1,806.69 × 719.78
4. Step 4: Simplify right side
   1,309.11x = 1,300,410.29
5. Step 5: Solve for x
   x = 1,300,410.29/1,309.11
6. Step 6: Final answer
   x = 993.35