Finding the Fourth Proportional to 42.88, 64.29 and 18.82

Step by Step Solution

1. Step 1: Write the proportion equation
   42.88 : 64.29 = 18.82 : x
2. Step 2: Convert to fraction form
   42.88/64.29 = 18.82/x
3. Step 3: Cross multiply
   42.88x = 64.29 × 18.82
4. Step 4: Simplify right side
   42.88x = 1,209.94
5. Step 5: Solve for x
   x = 1,209.94/42.88
6. Step 6: Final answer
   x = 28.22