Finding the Fourth Proportional to 1,317.31, 1,817.89 and 719.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,317.31 : 1,817.89 = 719.80 : x
2. Step 2: Convert to fraction form
   1,317.31/1,817.89 = 719.80/x
3. Step 3: Cross multiply
   1,317.31x = 1,817.89 × 719.80
4. Step 4: Simplify right side
   1,317.31x = 1,308,517.22
5. Step 5: Solve for x
   x = 1,308,517.22/1,317.31
6. Step 6: Final answer
   x = 993.33