Finding the Fourth Proportional to 2,128.59, 3,192.21 and 647.37

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.59 : 3,192.21 = 647.37 : x
2. Step 2: Convert to fraction form
   2,128.59/3,192.21 = 647.37/x
3. Step 3: Cross multiply
   2,128.59x = 3,192.21 × 647.37
4. Step 4: Simplify right side
   2,128.59x = 2,066,540.99
5. Step 5: Solve for x
   x = 2,066,540.99/2,128.59
6. Step 6: Final answer
   x = 970.85