Finding the Fourth Proportional to 2,171.16, 3,248.61 and 1,290.45

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.16 : 3,248.61 = 1,290.45 : x
2. Step 2: Convert to fraction form
   2,171.16/3,248.61 = 1,290.45/x
3. Step 3: Cross multiply
   2,171.16x = 3,248.61 × 1,290.45
4. Step 4: Simplify right side
   2,171.16x = 4,192,168.77
5. Step 5: Solve for x
   x = 4,192,168.77/2,171.16
6. Step 6: Final answer
   x = 1,930.84