Finding the Fourth Proportional to 86.72, 129.89 and 43.88

Step by Step Solution

1. Step 1: Write the proportion equation
   86.72 : 129.89 = 43.88 : x
2. Step 2: Convert to fraction form
   86.72/129.89 = 43.88/x
3. Step 3: Cross multiply
   86.72x = 129.89 × 43.88
4. Step 4: Simplify right side
   86.72x = 5,699.03
5. Step 5: Solve for x
   x = 5,699.03/86.72
6. Step 6: Final answer
   x = 65.72