Finding the Fourth Proportional to 127.72, 191.64 and 91.76

Step by Step Solution

1. Step 1: Write the proportion equation
   127.72 : 191.64 = 91.76 : x
2. Step 2: Convert to fraction form
   127.72/191.64 = 91.76/x
3. Step 3: Cross multiply
   127.72x = 191.64 × 91.76
4. Step 4: Simplify right side
   127.72x = 17,584.89
5. Step 5: Solve for x
   x = 17,584.89/127.72
6. Step 6: Final answer
   x = 137.68