Finding the Fourth Proportional to 78.76, 118.14 and 42.92

Step by Step Solution

1. Step 1: Write the proportion equation
   78.76 : 118.14 = 42.92 : x
2. Step 2: Convert to fraction form
   78.76/118.14 = 42.92/x
3. Step 3: Cross multiply
   78.76x = 118.14 × 42.92
4. Step 4: Simplify right side
   78.76x = 5,070.57
5. Step 5: Solve for x
   x = 5,070.57/78.76
6. Step 6: Final answer
   x = 64.38