Finding the Fourth Proportional to 86.35, 129.47 and 42.96

Step by Step Solution

1. Step 1: Write the proportion equation
   86.35 : 129.47 = 42.96 : x
2. Step 2: Convert to fraction form
   86.35/129.47 = 42.96/x
3. Step 3: Cross multiply
   86.35x = 129.47 × 42.96
4. Step 4: Simplify right side
   86.35x = 5,561.82
5. Step 5: Solve for x
   x = 5,561.82/86.35
6. Step 6: Final answer
   x = 64.41