Finding the Fourth Proportional to 42.91, 64.33 and 18.88

Step by Step Solution

1. Step 1: Write the proportion equation
   42.91 : 64.33 = 18.88 : x
2. Step 2: Convert to fraction form
   42.91/64.33 = 18.88/x
3. Step 3: Cross multiply
   42.91x = 64.33 × 18.88
4. Step 4: Simplify right side
   42.91x = 1,214.34
5. Step 5: Solve for x
   x = 1,214.34/42.91
6. Step 6: Final answer
   x = 28.30