Finding the Fourth Proportional to 1,320.20, 1,979.55 and 1,166.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.20 : 1,979.55 = 1,166.43 : x
2. Step 2: Convert to fraction form
   1,320.20/1,979.55 = 1,166.43/x
3. Step 3: Cross multiply
   1,320.20x = 1,979.55 × 1,166.43
4. Step 4: Simplify right side
   1,320.20x = 2,309,006.51
5. Step 5: Solve for x
   x = 2,309,006.51/1,320.20
6. Step 6: Final answer
   x = 1,748.99