Finding the Fourth Proportional to 2,611.58, 3,918.03 and 856.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,611.58 : 3,918.03 = 856.71 : x
2. Step 2: Convert to fraction form
   2,611.58/3,918.03 = 856.71/x
3. Step 3: Cross multiply
   2,611.58x = 3,918.03 × 856.71
4. Step 4: Simplify right side
   2,611.58x = 3,356,615.48
5. Step 5: Solve for x
   x = 3,356,615.48/2,611.58
6. Step 6: Final answer
   x = 1,285.28