Finding the Fourth Proportional to 89.00, 122.72 and 81.71

Step by Step Solution

1. Step 1: Write the proportion equation
   89.00 : 122.72 = 81.71 : x
2. Step 2: Convert to fraction form
   89.00/122.72 = 81.71/x
3. Step 3: Cross multiply
   89.00x = 122.72 × 81.71
4. Step 4: Simplify right side
   89.00x = 10,026.89
5. Step 5: Solve for x
   x = 10,026.89/89.00
6. Step 6: Final answer
   x = 112.66