Finding the Fourth Proportional to 1,397.63, 1,927.71 and 1,187.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.63 : 1,927.71 = 1,187.47 : x
2. Step 2: Convert to fraction form
   1,397.63/1,927.71 = 1,187.47/x
3. Step 3: Cross multiply
   1,397.63x = 1,927.71 × 1,187.47
4. Step 4: Simplify right side
   1,397.63x = 2,289,104.58
5. Step 5: Solve for x
   x = 2,289,104.58/1,397.63
6. Step 6: Final answer
   x = 1,637.85