Finding the Fourth Proportional to 3,661.51, 5,490.89 and 1,320.89

Step by Step Solution

1. Step 1: Write the proportion equation
   3,661.51 : 5,490.89 = 1,320.89 : x
2. Step 2: Convert to fraction form
   3,661.51/5,490.89 = 1,320.89/x
3. Step 3: Cross multiply
   3,661.51x = 5,490.89 × 1,320.89
4. Step 4: Simplify right side
   3,661.51x = 7,252,855.09
5. Step 5: Solve for x
   x = 7,252,855.09/3,661.51
6. Step 6: Final answer
   x = 1,980.84