Finding the Fourth Proportional to 89.82, 134.37 and 81.72

Step by Step Solution

1. Step 1: Write the proportion equation
   89.82 : 134.37 = 81.72 : x
2. Step 2: Convert to fraction form
   89.82/134.37 = 81.72/x
3. Step 3: Cross multiply
   89.82x = 134.37 × 81.72
4. Step 4: Simplify right side
   89.82x = 10,980.72
5. Step 5: Solve for x
   x = 10,980.72/89.82
6. Step 6: Final answer
   x = 122.25