Finding the Fourth Proportional to 77.15, 106.47 and 42.18

Step by Step Solution

1. Step 1: Write the proportion equation
   77.15 : 106.47 = 42.18 : x
2. Step 2: Convert to fraction form
   77.15/106.47 = 42.18/x
3. Step 3: Cross multiply
   77.15x = 106.47 × 42.18
4. Step 4: Simplify right side
   77.15x = 4,490.69
5. Step 5: Solve for x
   x = 4,490.69/77.15
6. Step 6: Final answer
   x = 58.21