Finding the Fourth Proportional to 80.72, 120.99 and 42.16

Step by Step Solution

1. Step 1: Write the proportion equation
   80.72 : 120.99 = 42.16 : x
2. Step 2: Convert to fraction form
   80.72/120.99 = 42.16/x
3. Step 3: Cross multiply
   80.72x = 120.99 × 42.16
4. Step 4: Simplify right side
   80.72x = 5,100.12
5. Step 5: Solve for x
   x = 5,100.12/80.72
6. Step 6: Final answer
   x = 63.19