Finding the Fourth Proportional to 99.78, 136.82 and 98.58

Step by Step Solution

1. Step 1: Write the proportion equation
   99.78 : 136.82 = 98.58 : x
2. Step 2: Convert to fraction form
   99.78/136.82 = 98.58/x
3. Step 3: Cross multiply
   99.78x = 136.82 × 98.58
4. Step 4: Simplify right side
   99.78x = 13,487.22
5. Step 5: Solve for x
   x = 13,487.22/99.78
6. Step 6: Final answer
   x = 135.17