Finding the Fourth Proportional to 6,858.78, 10,290.90 and 4,086.76

Step by Step Solution

1. Step 1: Write the proportion equation
   6,858.78 : 10,290.90 = 4,086.76 : x
2. Step 2: Convert to fraction form
   6,858.78/10,290.90 = 4,086.76/x
3. Step 3: Cross multiply
   6,858.78x = 10,290.90 × 4,086.76
4. Step 4: Simplify right side
   6,858.78x = 42,056,438.48
5. Step 5: Solve for x
   x = 42,056,438.48/6,858.78
6. Step 6: Final answer
   x = 6,131.77