Finding the Fourth Proportional to 3,785.26, 5,678.61 and 1,320.78

Step by Step Solution

1. Step 1: Write the proportion equation
   3,785.26 : 5,678.61 = 1,320.78 : x
2. Step 2: Convert to fraction form
   3,785.26/5,678.61 = 1,320.78/x
3. Step 3: Cross multiply
   3,785.26x = 5,678.61 × 1,320.78
4. Step 4: Simplify right side
   3,785.26x = 7,500,194.89
5. Step 5: Solve for x
   x = 7,500,194.89/3,785.26
6. Step 6: Final answer
   x = 1,981.42