Finding the Fourth Proportional to 1,389.64, 1,915.06 and 995.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.64 : 1,915.06 = 995.98 : x
2. Step 2: Convert to fraction form
   1,389.64/1,915.06 = 995.98/x
3. Step 3: Cross multiply
   1,389.64x = 1,915.06 × 995.98
4. Step 4: Simplify right side
   1,389.64x = 1,907,361.46
5. Step 5: Solve for x
   x = 1,907,361.46/1,389.64
6. Step 6: Final answer
   x = 1,372.56