Finding the Fourth Proportional to 91.48, 136.25 and 86.83

Step by Step Solution

1. Step 1: Write the proportion equation
   91.48 : 136.25 = 86.83 : x
2. Step 2: Convert to fraction form
   91.48/136.25 = 86.83/x
3. Step 3: Cross multiply
   91.48x = 136.25 × 86.83
4. Step 4: Simplify right side
   91.48x = 11,830.59
5. Step 5: Solve for x
   x = 11,830.59/91.48
6. Step 6: Final answer
   x = 129.32