Finding the Fourth Proportional to 1,389.65, 1,915.65 and 892.17

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.65 : 1,915.65 = 892.17 : x
2. Step 2: Convert to fraction form
   1,389.65/1,915.65 = 892.17/x
3. Step 3: Cross multiply
   1,389.65x = 1,915.65 × 892.17
4. Step 4: Simplify right side
   1,389.65x = 1,709,085.46
5. Step 5: Solve for x
   x = 1,709,085.46/1,389.65
6. Step 6: Final answer
   x = 1,229.87