Finding the Fourth Proportional to 99.38, 148.29 and 86.42

Step by Step Solution

1. Step 1: Write the proportion equation
   99.38 : 148.29 = 86.42 : x
2. Step 2: Convert to fraction form
   99.38/148.29 = 86.42/x
3. Step 3: Cross multiply
   99.38x = 148.29 × 86.42
4. Step 4: Simplify right side
   99.38x = 12,815.22
5. Step 5: Solve for x
   x = 12,815.22/99.38
6. Step 6: Final answer
   x = 128.95