Finding the Fourth Proportional to 80.61, 120.84 and 42.09

Step by Step Solution

1. Step 1: Write the proportion equation
   80.61 : 120.84 = 42.09 : x
2. Step 2: Convert to fraction form
   80.61/120.84 = 42.09/x
3. Step 3: Cross multiply
   80.61x = 120.84 × 42.09
4. Step 4: Simplify right side
   80.61x = 5,086.16
5. Step 5: Solve for x
   x = 5,086.16/80.61
6. Step 6: Final answer
   x = 63.10