Finding the Fourth Proportional to 1,317.59, 1,818.21 and 720.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,317.59 : 1,818.21 = 720.09 : x
2. Step 2: Convert to fraction form
   1,317.59/1,818.21 = 720.09/x
3. Step 3: Cross multiply
   1,317.59x = 1,818.21 × 720.09
4. Step 4: Simplify right side
   1,317.59x = 1,309,274.50
5. Step 5: Solve for x
   x = 1,309,274.50/1,317.59
6. Step 6: Final answer
   x = 993.69