Finding the Fourth Proportional to 28.01, 42.01 and 18.72

Step by Step Solution

1. Step 1: Write the proportion equation
   28.01 : 42.01 = 18.72 : x
2. Step 2: Convert to fraction form
   28.01/42.01 = 18.72/x
3. Step 3: Cross multiply
   28.01x = 42.01 × 18.72
4. Step 4: Simplify right side
   28.01x = 786.58
5. Step 5: Solve for x
   x = 786.58/28.01
6. Step 6: Final answer
   x = 28.08