Finding the Fourth Proportional to 117.57, 162.25 and 78.15

Step by Step Solution

1. Step 1: Write the proportion equation
   117.57 : 162.25 = 78.15 : x
2. Step 2: Convert to fraction form
   117.57/162.25 = 78.15/x
3. Step 3: Cross multiply
   117.57x = 162.25 × 78.15
4. Step 4: Simplify right side
   117.57x = 12,679.45
5. Step 5: Solve for x
   x = 12,679.45/117.57
6. Step 6: Final answer
   x = 107.85