Finding the Fourth Proportional to 91.83, 137.90 and 89.71

Step by Step Solution

1. Step 1: Write the proportion equation
   91.83 : 137.90 = 89.71 : x
2. Step 2: Convert to fraction form
   91.83/137.90 = 89.71/x
3. Step 3: Cross multiply
   91.83x = 137.90 × 89.71
4. Step 4: Simplify right side
   91.83x = 12,370.89
5. Step 5: Solve for x
   x = 12,370.89/91.83
6. Step 6: Final answer
   x = 134.71