Finding the Fourth Proportional to 1,398.86, 1,930.43 and 874.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.86 : 1,930.43 = 874.79 : x
2. Step 2: Convert to fraction form
   1,398.86/1,930.43 = 874.79/x
3. Step 3: Cross multiply
   1,398.86x = 1,930.43 × 874.79
4. Step 4: Simplify right side
   1,398.86x = 1,688,706.83
5. Step 5: Solve for x
   x = 1,688,706.83/1,398.86
6. Step 6: Final answer
   x = 1,207.21