Finding the Fourth Proportional to 1,575.78, 2,174.61 and 877.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,575.78 : 2,174.61 = 877.20 : x
2. Step 2: Convert to fraction form
   1,575.78/2,174.61 = 877.20/x
3. Step 3: Cross multiply
   1,575.78x = 2,174.61 × 877.20
4. Step 4: Simplify right side
   1,575.78x = 1,907,567.89
5. Step 5: Solve for x
   x = 1,907,567.89/1,575.78
6. Step 6: Final answer
   x = 1,210.55