Finding the Fourth Proportional to 111.72, 153.98 and 98.58

Step by Step Solution

1. Step 1: Write the proportion equation
   111.72 : 153.98 = 98.58 : x
2. Step 2: Convert to fraction form
   111.72/153.98 = 98.58/x
3. Step 3: Cross multiply
   111.72x = 153.98 × 98.58
4. Step 4: Simplify right side
   111.72x = 15,179.35
5. Step 5: Solve for x
   x = 15,179.35/111.72
6. Step 6: Final answer
   x = 135.87