Finding the Fourth Proportional to 2,112.72, 2,915.48 and 1,228.47

Step by Step Solution

1. Step 1: Write the proportion equation
   2,112.72 : 2,915.48 = 1,228.47 : x
2. Step 2: Convert to fraction form
   2,112.72/2,915.48 = 1,228.47/x
3. Step 3: Cross multiply
   2,112.72x = 2,915.48 × 1,228.47
4. Step 4: Simplify right side
   2,112.72x = 3,581,573.57
5. Step 5: Solve for x
   x = 3,581,573.57/2,112.72
6. Step 6: Final answer
   x = 1,695.24