Finding the Fourth Proportional to 89.76, 123.51 and 81.99

Step by Step Solution

1. Step 1: Write the proportion equation
   89.76 : 123.51 = 81.99 : x
2. Step 2: Convert to fraction form
   89.76/123.51 = 81.99/x
3. Step 3: Cross multiply
   89.76x = 123.51 × 81.99
4. Step 4: Simplify right side
   89.76x = 10,126.58
5. Step 5: Solve for x
   x = 10,126.58/89.76
6. Step 6: Final answer
   x = 112.82