Finding the Fourth Proportional to 99.88, 136.89 and 98.72

Step by Step Solution

1. Step 1: Write the proportion equation
   99.88 : 136.89 = 98.72 : x
2. Step 2: Convert to fraction form
   99.88/136.89 = 98.72/x
3. Step 3: Cross multiply
   99.88x = 136.89 × 98.72
4. Step 4: Simplify right side
   99.88x = 13,513.61
5. Step 5: Solve for x
   x = 13,513.61/99.88
6. Step 6: Final answer
   x = 135.30