Finding the Fourth Proportional to 91.72, 137.58 and 83.89

Step by Step Solution

1. Step 1: Write the proportion equation
   91.72 : 137.58 = 83.89 : x
2. Step 2: Convert to fraction form
   91.72/137.58 = 83.89/x
3. Step 3: Cross multiply
   91.72x = 137.58 × 83.89
4. Step 4: Simplify right side
   91.72x = 11,540.48
5. Step 5: Solve for x
   x = 11,540.48/91.72
6. Step 6: Final answer
   x = 125.83