Finding the Fourth Proportional to 1,389.56, 1,919.16 and 946.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.56 : 1,919.16 = 946.72 : x
2. Step 2: Convert to fraction form
   1,389.56/1,919.16 = 946.72/x
3. Step 3: Cross multiply
   1,389.56x = 1,919.16 × 946.72
4. Step 4: Simplify right side
   1,389.56x = 1,816,907.16
5. Step 5: Solve for x
   x = 1,816,907.16/1,389.56
6. Step 6: Final answer
   x = 1,307.54