Finding the Fourth Proportional to 99.97, 149.78 and 72.88

Step by Step Solution

1. Step 1: Write the proportion equation
   99.97 : 149.78 = 72.88 : x
2. Step 2: Convert to fraction form
   99.97/149.78 = 72.88/x
3. Step 3: Cross multiply
   99.97x = 149.78 × 72.88
4. Step 4: Simplify right side
   99.97x = 10,915.77
5. Step 5: Solve for x
   x = 10,915.77/99.97
6. Step 6: Final answer
   x = 109.19