Finding the Fourth Proportional to 100.45, 138.55 and 69.42

Step by Step Solution

1. Step 1: Write the proportion equation
   100.45 : 138.55 = 69.42 : x
2. Step 2: Convert to fraction form
   100.45/138.55 = 69.42/x
3. Step 3: Cross multiply
   100.45x = 138.55 × 69.42
4. Step 4: Simplify right side
   100.45x = 9,618.10
5. Step 5: Solve for x
   x = 9,618.10/100.45
6. Step 6: Final answer
   x = 95.75