Finding the Fourth Proportional to 1,580.72, 2,181.39 and 872.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,580.72 : 2,181.39 = 872.61 : x
2. Step 2: Convert to fraction form
   1,580.72/2,181.39 = 872.61/x
3. Step 3: Cross multiply
   1,580.72x = 2,181.39 × 872.61
4. Step 4: Simplify right side
   1,580.72x = 1,903,503.55
5. Step 5: Solve for x
   x = 1,903,503.55/1,580.72
6. Step 6: Final answer
   x = 1,204.20