Finding the Fourth Proportional to 91.76, 126.72 and 86.65

Step by Step Solution

1. Step 1: Write the proportion equation
   91.76 : 126.72 = 86.65 : x
2. Step 2: Convert to fraction form
   91.76/126.72 = 86.65/x
3. Step 3: Cross multiply
   91.76x = 126.72 × 86.65
4. Step 4: Simplify right side
   91.76x = 10,980.29
5. Step 5: Solve for x
   x = 10,980.29/91.76
6. Step 6: Final answer
   x = 119.66