Finding the Fourth Proportional to 1,872.81, 2,805.56 and 1,221.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,872.81 : 2,805.56 = 1,221.57 : x
2. Step 2: Convert to fraction form
   1,872.81/2,805.56 = 1,221.57/x
3. Step 3: Cross multiply
   1,872.81x = 2,805.56 × 1,221.57
4. Step 4: Simplify right side
   1,872.81x = 3,427,181.82
5. Step 5: Solve for x
   x = 3,427,181.82/1,872.81
6. Step 6: Final answer
   x = 1,829.97