Finding the Fourth Proportional to 28.42, 42.72 and 28.16

Step by Step Solution

1. Step 1: Write the proportion equation
   28.42 : 42.72 = 28.16 : x
2. Step 2: Convert to fraction form
   28.42/42.72 = 28.16/x
3. Step 3: Cross multiply
   28.42x = 42.72 × 28.16
4. Step 4: Simplify right side
   28.42x = 1,203.00
5. Step 5: Solve for x
   x = 1,203.00/28.42
6. Step 6: Final answer
   x = 42.33