Finding the Fourth Proportional to 42.88, 64.68 and 42.16

Step by Step Solution

1. Step 1: Write the proportion equation
   42.88 : 64.68 = 42.16 : x
2. Step 2: Convert to fraction form
   42.88/64.68 = 42.16/x
3. Step 3: Cross multiply
   42.88x = 64.68 × 42.16
4. Step 4: Simplify right side
   42.88x = 2,726.91
5. Step 5: Solve for x
   x = 2,726.91/42.88
6. Step 6: Final answer
   x = 63.59