Finding the Fourth Proportional to 1,398.38, 1,929.78 and 874.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.38 : 1,929.78 = 874.72 : x
2. Step 2: Convert to fraction form
   1,398.38/1,929.78 = 874.72/x
3. Step 3: Cross multiply
   1,398.38x = 1,929.78 × 874.72
4. Step 4: Simplify right side
   1,398.38x = 1,688,017.16
5. Step 5: Solve for x
   x = 1,688,017.16/1,398.38
6. Step 6: Final answer
   x = 1,207.12