Finding the Fourth Proportional to 102.52, 153.42 and 78.28

Step by Step Solution

1. Step 1: Write the proportion equation
   102.52 : 153.42 = 78.28 : x
2. Step 2: Convert to fraction form
   102.52/153.42 = 78.28/x
3. Step 3: Cross multiply
   102.52x = 153.42 × 78.28
4. Step 4: Simplify right side
   102.52x = 12,009.72
5. Step 5: Solve for x
   x = 12,009.72/102.52
6. Step 6: Final answer
   x = 117.15