Finding the Fourth Proportional to 100.10, 138.06 and 72.38

Step by Step Solution

1. Step 1: Write the proportion equation
   100.10 : 138.06 = 72.38 : x
2. Step 2: Convert to fraction form
   100.10/138.06 = 72.38/x
3. Step 3: Cross multiply
   100.10x = 138.06 × 72.38
4. Step 4: Simplify right side
   100.10x = 9,992.78
5. Step 5: Solve for x
   x = 9,992.78/100.10
6. Step 6: Final answer
   x = 99.83