Finding the Fourth Proportional to 112.78, 155.82 and 100.54

Step by Step Solution

1. Step 1: Write the proportion equation
   112.78 : 155.82 = 100.54 : x
2. Step 2: Convert to fraction form
   112.78/155.82 = 100.54/x
3. Step 3: Cross multiply
   112.78x = 155.82 × 100.54
4. Step 4: Simplify right side
   112.78x = 15,666.14
5. Step 5: Solve for x
   x = 15,666.14/112.78
6. Step 6: Final answer
   x = 138.91