Finding the Fourth Proportional to 1,320.05, 1,819.70 and 1,039.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.05 : 1,819.70 = 1,039.72 : x
2. Step 2: Convert to fraction form
   1,320.05/1,819.70 = 1,039.72/x
3. Step 3: Cross multiply
   1,320.05x = 1,819.70 × 1,039.72
4. Step 4: Simplify right side
   1,320.05x = 1,891,976.05
5. Step 5: Solve for x
   x = 1,891,976.05/1,320.05
6. Step 6: Final answer
   x = 1,433.26