Finding the Fourth Proportional to 1,915.35, 2,870.28 and 819.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.35 : 2,870.28 = 819.42 : x
2. Step 2: Convert to fraction form
   1,915.35/2,870.28 = 819.42/x
3. Step 3: Cross multiply
   1,915.35x = 2,870.28 × 819.42
4. Step 4: Simplify right side
   1,915.35x = 2,351,964.84
5. Step 5: Solve for x
   x = 2,351,964.84/1,915.35
6. Step 6: Final answer
   x = 1,227.96