Finding the Fourth Proportional to 1,422.38, 1,958.79 and 1,221.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,422.38 : 1,958.79 = 1,221.59 : x
2. Step 2: Convert to fraction form
   1,422.38/1,958.79 = 1,221.59/x
3. Step 3: Cross multiply
   1,422.38x = 1,958.79 × 1,221.59
4. Step 4: Simplify right side
   1,422.38x = 2,392,843.17
5. Step 5: Solve for x
   x = 2,392,843.17/1,422.38
6. Step 6: Final answer
   x = 1,682.29