Finding the Fourth Proportional to 1,915.16, 2,870.24 and 1,389.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.16 : 2,870.24 = 1,389.83 : x
2. Step 2: Convert to fraction form
   1,915.16/2,870.24 = 1,389.83/x
3. Step 3: Cross multiply
   1,915.16x = 2,870.24 × 1,389.83
4. Step 4: Simplify right side
   1,915.16x = 3,989,124.36
5. Step 5: Solve for x
   x = 3,989,124.36/1,915.16
6. Step 6: Final answer
   x = 2,082.93