Finding the Fourth Proportional to 1,389.63, 1,915.71 and 946.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.63 : 1,915.71 = 946.96 : x
2. Step 2: Convert to fraction form
   1,389.63/1,915.71 = 946.96/x
3. Step 3: Cross multiply
   1,389.63x = 1,915.71 × 946.96
4. Step 4: Simplify right side
   1,389.63x = 1,814,096.01
5. Step 5: Solve for x
   x = 1,814,096.01/1,389.63
6. Step 6: Final answer
   x = 1,305.46