Finding the Fourth Proportional to 7,085.87, 9,778.71 and 3,899.00

Step by Step Solution

1. Step 1: Write the proportion equation
   7,085.87 : 9,778.71 = 3,899.00 : x
2. Step 2: Convert to fraction form
   7,085.87/9,778.71 = 3,899.00/x
3. Step 3: Cross multiply
   7,085.87x = 9,778.71 × 3,899.00
4. Step 4: Simplify right side
   7,085.87x = 38,127,141.40
5. Step 5: Solve for x
   x = 38,127,141.40/7,085.87
6. Step 6: Final answer
   x = 5,380.73