Finding the Fourth Proportional to 42.78, 64.18 and 34.22

Step by Step Solution

1. Step 1: Write the proportion equation
   42.78 : 64.18 = 34.22 : x
2. Step 2: Convert to fraction form
   42.78/64.18 = 34.22/x
3. Step 3: Cross multiply
   42.78x = 64.18 × 34.22
4. Step 4: Simplify right side
   42.78x = 2,196.24
5. Step 5: Solve for x
   x = 2,196.24/42.78
6. Step 6: Final answer
   x = 51.34