Finding the Fourth Proportional to 1,620.40, 2,238.72 and 1,540.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.40 : 2,238.72 = 1,540.48 : x
2. Step 2: Convert to fraction form
   1,620.40/2,238.72 = 1,540.48/x
3. Step 3: Cross multiply
   1,620.40x = 2,238.72 × 1,540.48
4. Step 4: Simplify right side
   1,620.40x = 3,448,703.39
5. Step 5: Solve for x
   x = 3,448,703.39/1,620.40
6. Step 6: Final answer
   x = 2,128.30