Finding the Fourth Proportional to 1,429.90, 1,978.64 and 1,219.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.90 : 1,978.64 = 1,219.74 : x
2. Step 2: Convert to fraction form
   1,429.90/1,978.64 = 1,219.74/x
3. Step 3: Cross multiply
   1,429.90x = 1,978.64 × 1,219.74
4. Step 4: Simplify right side
   1,429.90x = 2,413,426.35
5. Step 5: Solve for x
   x = 2,413,426.35/1,429.90
6. Step 6: Final answer
   x = 1,687.83