Finding the Fourth Proportional to 114.91, 172.38 and 42.78

Step by Step Solution

1. Step 1: Write the proportion equation
   114.91 : 172.38 = 42.78 : x
2. Step 2: Convert to fraction form
   114.91/172.38 = 42.78/x
3. Step 3: Cross multiply
   114.91x = 172.38 × 42.78
4. Step 4: Simplify right side
   114.91x = 7,374.42
5. Step 5: Solve for x
   x = 7,374.42/114.91
6. Step 6: Final answer
   x = 64.18