Finding the Fourth Proportional to 3,785.89, 5,679.59 and 1,320.05

Step by Step Solution

1. Step 1: Write the proportion equation
   3,785.89 : 5,679.59 = 1,320.05 : x
2. Step 2: Convert to fraction form
   3,785.89/5,679.59 = 1,320.05/x
3. Step 3: Cross multiply
   3,785.89x = 5,679.59 × 1,320.05
4. Step 4: Simplify right side
   3,785.89x = 7,497,317.68
5. Step 5: Solve for x
   x = 7,497,317.68/3,785.89
6. Step 6: Final answer
   x = 1,980.33