Finding the Fourth Proportional to 3,661.45, 5,488.81 and 1,320.91

Step by Step Solution

1. Step 1: Write the proportion equation
   3,661.45 : 5,488.81 = 1,320.91 : x
2. Step 2: Convert to fraction form
   3,661.45/5,488.81 = 1,320.91/x
3. Step 3: Cross multiply
   3,661.45x = 5,488.81 × 1,320.91
4. Step 4: Simplify right side
   3,661.45x = 7,250,214.42
5. Step 5: Solve for x
   x = 7,250,214.42/3,661.45
6. Step 6: Final answer
   x = 1,980.15