Finding the Fourth Proportional to 100.42, 138.72 and 82.06

Step by Step Solution

1. Step 1: Write the proportion equation
   100.42 : 138.72 = 82.06 : x
2. Step 2: Convert to fraction form
   100.42/138.72 = 82.06/x
3. Step 3: Cross multiply
   100.42x = 138.72 × 82.06
4. Step 4: Simplify right side
   100.42x = 11,383.36
5. Step 5: Solve for x
   x = 11,383.36/100.42
6. Step 6: Final answer
   x = 113.36