Finding the Fourth Proportional to 100.17, 138.04 and 72.49

Step by Step Solution

1. Step 1: Write the proportion equation
   100.17 : 138.04 = 72.49 : x
2. Step 2: Convert to fraction form
   100.17/138.04 = 72.49/x
3. Step 3: Cross multiply
   100.17x = 138.04 × 72.49
4. Step 4: Simplify right side
   100.17x = 10,006.52
5. Step 5: Solve for x
   x = 10,006.52/100.17
6. Step 6: Final answer
   x = 99.90