Finding the Fourth Proportional to 2,015.96, 3,020.49 and 1,321.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,015.96 : 3,020.49 = 1,321.79 : x
2. Step 2: Convert to fraction form
   2,015.96/3,020.49 = 1,321.79/x
3. Step 3: Cross multiply
   2,015.96x = 3,020.49 × 1,321.79
4. Step 4: Simplify right side
   2,015.96x = 3,992,438.37
5. Step 5: Solve for x
   x = 3,992,438.37/2,015.96
6. Step 6: Final answer
   x = 1,980.42