Finding the Fourth Proportional to 1,389.51, 1,913.15 and 1,179.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.51 : 1,913.15 = 1,179.25 : x
2. Step 2: Convert to fraction form
   1,389.51/1,913.15 = 1,179.25/x
3. Step 3: Cross multiply
   1,389.51x = 1,913.15 × 1,179.25
4. Step 4: Simplify right side
   1,389.51x = 2,256,080.30
5. Step 5: Solve for x
   x = 2,256,080.30/1,389.51
6. Step 6: Final answer
   x = 1,623.65