Finding the Fourth Proportional to 111.71, 154.37 and 100.64

Step by Step Solution

1. Step 1: Write the proportion equation
   111.71 : 154.37 = 100.64 : x
2. Step 2: Convert to fraction form
   111.71/154.37 = 100.64/x
3. Step 3: Cross multiply
   111.71x = 154.37 × 100.64
4. Step 4: Simplify right side
   111.71x = 15,536.43
5. Step 5: Solve for x
   x = 15,536.43/111.71
6. Step 6: Final answer
   x = 139.08