Finding the Fourth Proportional to 2,112.84, 3,171.06 and 815.22

Step by Step Solution

1. Step 1: Write the proportion equation
   2,112.84 : 3,171.06 = 815.22 : x
2. Step 2: Convert to fraction form
   2,112.84/3,171.06 = 815.22/x
3. Step 3: Cross multiply
   2,112.84x = 3,171.06 × 815.22
4. Step 4: Simplify right side
   2,112.84x = 2,585,111.53
5. Step 5: Solve for x
   x = 2,585,111.53/2,112.84
6. Step 6: Final answer
   x = 1,223.52