Finding the Fourth Proportional to 1,436.70, 1,981.41 and 1,290.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,436.70 : 1,981.41 = 1,290.90 : x
2. Step 2: Convert to fraction form
   1,436.70/1,981.41 = 1,290.90/x
3. Step 3: Cross multiply
   1,436.70x = 1,981.41 × 1,290.90
4. Step 4: Simplify right side
   1,436.70x = 2,557,812.02
5. Step 5: Solve for x
   x = 2,557,812.02/1,436.70
6. Step 6: Final answer
   x = 1,780.33