Finding the Fourth Proportional to 86.24, 128.72 and 75.52

Step by Step Solution

1. Step 1: Write the proportion equation
   86.24 : 128.72 = 75.52 : x
2. Step 2: Convert to fraction form
   86.24/128.72 = 75.52/x
3. Step 3: Cross multiply
   86.24x = 128.72 × 75.52
4. Step 4: Simplify right side
   86.24x = 9,720.93
5. Step 5: Solve for x
   x = 9,720.93/86.24
6. Step 6: Final answer
   x = 112.72