Finding the Fourth Proportional to 100.34, 137.91 and 88.61

Step by Step Solution

1. Step 1: Write the proportion equation
   100.34 : 137.91 = 88.61 : x
2. Step 2: Convert to fraction form
   100.34/137.91 = 88.61/x
3. Step 3: Cross multiply
   100.34x = 137.91 × 88.61
4. Step 4: Simplify right side
   100.34x = 12,220.55
5. Step 5: Solve for x
   x = 12,220.55/100.34
6. Step 6: Final answer
   x = 121.79