Finding the Fourth Proportional to 1,580.91, 2,181.71 and 872.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,580.91 : 2,181.71 = 872.78 : x
2. Step 2: Convert to fraction form
   1,580.91/2,181.71 = 872.78/x
3. Step 3: Cross multiply
   1,580.91x = 2,181.71 × 872.78
4. Step 4: Simplify right side
   1,580.91x = 1,904,137.58
5. Step 5: Solve for x
   x = 1,904,137.58/1,580.91
6. Step 6: Final answer
   x = 1,204.46