Finding the Fourth Proportional to 5,405.31, 8,111.61 and 2,118

Step by Step Solution

1. Step 1: Write the proportion equation
   5,405.31 : 8,111.61 = 2,118 : x
2. Step 2: Convert to fraction form
   5,405.31/8,111.61 = 2,118/x
3. Step 3: Cross multiply
   5,405.31x = 8,111.61 × 2,118
4. Step 4: Simplify right side
   5,405.31x = 17,180,389.98
5. Step 5: Solve for x
   x = 17,180,389.98/5,405.31
6. Step 6: Final answer
   x = 3,178.43