Finding the Fourth Proportional to 97.89, 146.91 and 86.50

Step by Step Solution

1. Step 1: Write the proportion equation
   97.89 : 146.91 = 86.50 : x
2. Step 2: Convert to fraction form
   97.89/146.91 = 86.50/x
3. Step 3: Cross multiply
   97.89x = 146.91 × 86.50
4. Step 4: Simplify right side
   97.89x = 12,707.72
5. Step 5: Solve for x
   x = 12,707.72/97.89
6. Step 6: Final answer
   x = 129.82