Finding the Fourth Proportional to 78.88, 118.36 and 42.88

Step by Step Solution

1. Step 1: Write the proportion equation
   78.88 : 118.36 = 42.88 : x
2. Step 2: Convert to fraction form
   78.88/118.36 = 42.88/x
3. Step 3: Cross multiply
   78.88x = 118.36 × 42.88
4. Step 4: Simplify right side
   78.88x = 5,075.28
5. Step 5: Solve for x
   x = 5,075.28/78.88
6. Step 6: Final answer
   x = 64.34