Finding the Fourth Proportional to 5,142.49, 7,714.78 and 1,678.81

Step by Step Solution

1. Step 1: Write the proportion equation
   5,142.49 : 7,714.78 = 1,678.81 : x
2. Step 2: Convert to fraction form
   5,142.49/7,714.78 = 1,678.81/x
3. Step 3: Cross multiply
   5,142.49x = 7,714.78 × 1,678.81
4. Step 4: Simplify right side
   5,142.49x = 12,951,641.42
5. Step 5: Solve for x
   x = 12,951,641.42/5,142.49
6. Step 6: Final answer
   x = 2,518.55