Finding the Fourth Proportional to 89.31, 123.09 and 71.79

Step by Step Solution

1. Step 1: Write the proportion equation
   89.31 : 123.09 = 71.79 : x
2. Step 2: Convert to fraction form
   89.31/123.09 = 71.79/x
3. Step 3: Cross multiply
   89.31x = 123.09 × 71.79
4. Step 4: Simplify right side
   89.31x = 8,836.02
5. Step 5: Solve for x
   x = 8,836.02/89.31
6. Step 6: Final answer
   x = 98.94