Finding the Fourth Proportional to 279.31, 418.71 and 142.05

Step by Step Solution

1. Step 1: Write the proportion equation
   279.31 : 418.71 = 142.05 : x
2. Step 2: Convert to fraction form
   279.31/418.71 = 142.05/x
3. Step 3: Cross multiply
   279.31x = 418.71 × 142.05
4. Step 4: Simplify right side
   279.31x = 59,478.86
5. Step 5: Solve for x
   x = 59,478.86/279.31
6. Step 6: Final answer
   x = 212.95