Finding the Fourth Proportional to 1,298.61, 1,790.28 and 878.29

Step by Step Solution

1. Step 1: Write the proportion equation
   1,298.61 : 1,790.28 = 878.29 : x
2. Step 2: Convert to fraction form
   1,298.61/1,790.28 = 878.29/x
3. Step 3: Cross multiply
   1,298.61x = 1,790.28 × 878.29
4. Step 4: Simplify right side
   1,298.61x = 1,572,388.15
5. Step 5: Solve for x
   x = 1,572,388.15/1,298.61
6. Step 6: Final answer
   x = 1,210.83