Finding the Fourth Proportional to 114.78, 171.69 and 78.30

Step by Step Solution

1. Step 1: Write the proportion equation
   114.78 : 171.69 = 78.30 : x
2. Step 2: Convert to fraction form
   114.78/171.69 = 78.30/x
3. Step 3: Cross multiply
   114.78x = 171.69 × 78.30
4. Step 4: Simplify right side
   114.78x = 13,443.33
5. Step 5: Solve for x
   x = 13,443.33/114.78
6. Step 6: Final answer
   x = 117.12