Finding the Fourth Proportional to 2,120.31, 3,180.56 and 581.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,120.31 : 3,180.56 = 581.31 : x
2. Step 2: Convert to fraction form
   2,120.31/3,180.56 = 581.31/x
3. Step 3: Cross multiply
   2,120.31x = 3,180.56 × 581.31
4. Step 4: Simplify right side
   2,120.31x = 1,848,899.29
5. Step 5: Solve for x
   x = 1,848,899.29/2,120.31
6. Step 6: Final answer
   x = 871.99