Finding the Fourth Proportional to 1,351.61, 1,865.52 and 878.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,351.61 : 1,865.52 = 878.69 : x
2. Step 2: Convert to fraction form
   1,351.61/1,865.52 = 878.69/x
3. Step 3: Cross multiply
   1,351.61x = 1,865.52 × 878.69
4. Step 4: Simplify right side
   1,351.61x = 1,639,213.77
5. Step 5: Solve for x
   x = 1,639,213.77/1,351.61
6. Step 6: Final answer
   x = 1,212.79