Finding the Fourth Proportional to 86.28, 129.43 and 42.94

Step by Step Solution

1. Step 1: Write the proportion equation
   86.28 : 129.43 = 42.94 : x
2. Step 2: Convert to fraction form
   86.28/129.43 = 42.94/x
3. Step 3: Cross multiply
   86.28x = 129.43 × 42.94
4. Step 4: Simplify right side
   86.28x = 5,557.72
5. Step 5: Solve for x
   x = 5,557.72/86.28
6. Step 6: Final answer
   x = 64.42