Finding the Fourth Proportional to 100.24, 138.27 and 72.57

Step by Step Solution

1. Step 1: Write the proportion equation
   100.24 : 138.27 = 72.57 : x
2. Step 2: Convert to fraction form
   100.24/138.27 = 72.57/x
3. Step 3: Cross multiply
   100.24x = 138.27 × 72.57
4. Step 4: Simplify right side
   100.24x = 10,034.25
5. Step 5: Solve for x
   x = 10,034.25/100.24
6. Step 6: Final answer
   x = 100.10