Finding the Fourth Proportional to 2,015.31, 2,780.42 and 1,317.09

Step by Step Solution

1. Step 1: Write the proportion equation
   2,015.31 : 2,780.42 = 1,317.09 : x
2. Step 2: Convert to fraction form
   2,015.31/2,780.42 = 1,317.09/x
3. Step 3: Cross multiply
   2,015.31x = 2,780.42 × 1,317.09
4. Step 4: Simplify right side
   2,015.31x = 3,662,056.79
5. Step 5: Solve for x
   x = 3,662,056.79/2,015.31
6. Step 6: Final answer
   x = 1,817.12