Finding the Fourth Proportional to 86.72, 118.71 and 86.43

Step by Step Solution

1. Step 1: Write the proportion equation
   86.72 : 118.71 = 86.43 : x
2. Step 2: Convert to fraction form
   86.72/118.71 = 86.43/x
3. Step 3: Cross multiply
   86.72x = 118.71 × 86.43
4. Step 4: Simplify right side
   86.72x = 10,260.11
5. Step 5: Solve for x
   x = 10,260.11/86.72
6. Step 6: Final answer
   x = 118.32