Finding the Fourth Proportional to 131.72, 181.82 and 86.86

Step by Step Solution

1. Step 1: Write the proportion equation
   131.72 : 181.82 = 86.86 : x
2. Step 2: Convert to fraction form
   131.72/181.82 = 86.86/x
3. Step 3: Cross multiply
   131.72x = 181.82 × 86.86
4. Step 4: Simplify right side
   131.72x = 15,792.89
5. Step 5: Solve for x
   x = 15,792.89/131.72
6. Step 6: Final answer
   x = 119.90