Finding the Fourth Proportional to 1,389.63, 1,918.47 and 964.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.63 : 1,918.47 = 964.89 : x
2. Step 2: Convert to fraction form
   1,389.63/1,918.47 = 964.89/x
3. Step 3: Cross multiply
   1,389.63x = 1,918.47 × 964.89
4. Step 4: Simplify right side
   1,389.63x = 1,851,116.14
5. Step 5: Solve for x
   x = 1,851,116.14/1,389.63
6. Step 6: Final answer
   x = 1,332.09