Finding the Fourth Proportional to 2,486.81, 3,729.42 and 820.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,486.81 : 3,729.42 = 820.56 : x
2. Step 2: Convert to fraction form
   2,486.81/3,729.42 = 820.56/x
3. Step 3: Cross multiply
   2,486.81x = 3,729.42 × 820.56
4. Step 4: Simplify right side
   2,486.81x = 3,060,224.25
5. Step 5: Solve for x
   x = 3,060,224.25/2,486.81
6. Step 6: Final answer
   x = 1,230.58