Finding the Fourth Proportional to 103.57, 155.37 and 86.56

Step by Step Solution

1. Step 1: Write the proportion equation
   103.57 : 155.37 = 86.56 : x
2. Step 2: Convert to fraction form
   103.57/155.37 = 86.56/x
3. Step 3: Cross multiply
   103.57x = 155.37 × 86.56
4. Step 4: Simplify right side
   103.57x = 13,448.83
5. Step 5: Solve for x
   x = 13,448.83/103.57
6. Step 6: Final answer
   x = 129.85