Finding the Fourth Proportional to 86.32, 129.50 and 43.57

Step by Step Solution

1. Step 1: Write the proportion equation
   86.32 : 129.50 = 43.57 : x
2. Step 2: Convert to fraction form
   86.32/129.50 = 43.57/x
3. Step 3: Cross multiply
   86.32x = 129.50 × 43.57
4. Step 4: Simplify right side
   86.32x = 5,642.10
5. Step 5: Solve for x
   x = 5,642.10/86.32
6. Step 6: Final answer
   x = 65.36