Finding the Fourth Proportional to 86.30, 129.33 and 42.96

Step by Step Solution

1. Step 1: Write the proportion equation
   86.30 : 129.33 = 42.96 : x
2. Step 2: Convert to fraction form
   86.30/129.33 = 42.96/x
3. Step 3: Cross multiply
   86.30x = 129.33 × 42.96
4. Step 4: Simplify right side
   86.30x = 5,556.02
5. Step 5: Solve for x
   x = 5,556.02/86.30
6. Step 6: Final answer
   x = 64.38