Finding the Fourth Proportional to 1,577.41, 2,176.81 and 878.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,577.41 : 2,176.81 = 878.78 : x
2. Step 2: Convert to fraction form
   1,577.41/2,176.81 = 878.78/x
3. Step 3: Cross multiply
   1,577.41x = 2,176.81 × 878.78
4. Step 4: Simplify right side
   1,577.41x = 1,912,940.34
5. Step 5: Solve for x
   x = 1,912,940.34/1,577.41
6. Step 6: Final answer
   x = 1,212.71