Finding the Fourth Proportional to 1,389.34, 1,917.12 and 865.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.34 : 1,917.12 = 865.18 : x
2. Step 2: Convert to fraction form
   1,389.34/1,917.12 = 865.18/x
3. Step 3: Cross multiply
   1,389.34x = 1,917.12 × 865.18
4. Step 4: Simplify right side
   1,389.34x = 1,658,653.88
5. Step 5: Solve for x
   x = 1,658,653.88/1,389.34
6. Step 6: Final answer
   x = 1,193.84