Finding the Fourth Proportional to 1,388.96, 1,915.88 and 892.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.96 : 1,915.88 = 892.23 : x
2. Step 2: Convert to fraction form
   1,388.96/1,915.88 = 892.23/x
3. Step 3: Cross multiply
   1,388.96x = 1,915.88 × 892.23
4. Step 4: Simplify right side
   1,388.96x = 1,709,405.61
5. Step 5: Solve for x
   x = 1,709,405.61/1,388.96
6. Step 6: Final answer
   x = 1,230.71