Finding the Fourth Proportional to 28.33, 42.37 and 20.72

Step by Step Solution

1. Step 1: Write the proportion equation
   28.33 : 42.37 = 20.72 : x
2. Step 2: Convert to fraction form
   28.33/42.37 = 20.72/x
3. Step 3: Cross multiply
   28.33x = 42.37 × 20.72
4. Step 4: Simplify right side
   28.33x = 877.91
5. Step 5: Solve for x
   x = 877.91/28.33
6. Step 6: Final answer
   x = 30.99