Finding the Fourth Proportional to 78.57, 117.99 and 42.66

Step by Step Solution

1. Step 1: Write the proportion equation
   78.57 : 117.99 = 42.66 : x
2. Step 2: Convert to fraction form
   78.57/117.99 = 42.66/x
3. Step 3: Cross multiply
   78.57x = 117.99 × 42.66
4. Step 4: Simplify right side
   78.57x = 5,033.45
5. Step 5: Solve for x
   x = 5,033.45/78.57
6. Step 6: Final answer
   x = 64.06