Finding the Fourth Proportional to 1,336.20, 2,005.05 and 719.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,336.20 : 2,005.05 = 719.89 : x
2. Step 2: Convert to fraction form
   1,336.20/2,005.05 = 719.89/x
3. Step 3: Cross multiply
   1,336.20x = 2,005.05 × 719.89
4. Step 4: Simplify right side
   1,336.20x = 1,443,401.82
5. Step 5: Solve for x
   x = 1,443,401.82/1,336.20
6. Step 6: Final answer
   x = 1,080.23