Finding the Fourth Proportional to 1,398.89, 1,930.44 and 875.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.89 : 1,930.44 = 875.21 : x
2. Step 2: Convert to fraction form
   1,398.89/1,930.44 = 875.21/x
3. Step 3: Cross multiply
   1,398.89x = 1,930.44 × 875.21
4. Step 4: Simplify right side
   1,398.89x = 1,689,540.39
5. Step 5: Solve for x
   x = 1,689,540.39/1,398.89
6. Step 6: Final answer
   x = 1,207.77