Finding the Fourth Proportional to 78.95, 118.49 and 42.87

Step by Step Solution

1. Step 1: Write the proportion equation
   78.95 : 118.49 = 42.87 : x
2. Step 2: Convert to fraction form
   78.95/118.49 = 42.87/x
3. Step 3: Cross multiply
   78.95x = 118.49 × 42.87
4. Step 4: Simplify right side
   78.95x = 5,079.45
5. Step 5: Solve for x
   x = 5,079.45/78.95
6. Step 6: Final answer
   x = 64.34