Finding the Fourth Proportional to 100.16, 138.32 and 72.56

Step by Step Solution

1. Step 1: Write the proportion equation
   100.16 : 138.32 = 72.56 : x
2. Step 2: Convert to fraction form
   100.16/138.32 = 72.56/x
3. Step 3: Cross multiply
   100.16x = 138.32 × 72.56
4. Step 4: Simplify right side
   100.16x = 10,036.50
5. Step 5: Solve for x
   x = 10,036.50/100.16
6. Step 6: Final answer
   x = 100.20