Finding the Fourth Proportional to 89.23, 123.09 and 72.79

Step by Step Solution

1. Step 1: Write the proportion equation
   89.23 : 123.09 = 72.79 : x
2. Step 2: Convert to fraction form
   89.23/123.09 = 72.79/x
3. Step 3: Cross multiply
   89.23x = 123.09 × 72.79
4. Step 4: Simplify right side
   89.23x = 8,959.72
5. Step 5: Solve for x
   x = 8,959.72/89.23
6. Step 6: Final answer
   x = 100.41