Finding the Fourth Proportional to 78.73, 117.89 and 65.86

Step by Step Solution

1. Step 1: Write the proportion equation
   78.73 : 117.89 = 65.86 : x
2. Step 2: Convert to fraction form
   78.73/117.89 = 65.86/x
3. Step 3: Cross multiply
   78.73x = 117.89 × 65.86
4. Step 4: Simplify right side
   78.73x = 7,763.76
5. Step 5: Solve for x
   x = 7,763.76/78.73
6. Step 6: Final answer
   x = 98.62