Finding the Fourth Proportional to 111.69, 154.17 and 100.56

Step by Step Solution

1. Step 1: Write the proportion equation
   111.69 : 154.17 = 100.56 : x
2. Step 2: Convert to fraction form
   111.69/154.17 = 100.56/x
3. Step 3: Cross multiply
   111.69x = 154.17 × 100.56
4. Step 4: Simplify right side
   111.69x = 15,503.34
5. Step 5: Solve for x
   x = 15,503.34/111.69
6. Step 6: Final answer
   x = 138.81