Finding the Fourth Proportional to 1,290.86, 1,938.57 and 961.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.86 : 1,938.57 = 961.89 : x
2. Step 2: Convert to fraction form
   1,290.86/1,938.57 = 961.89/x
3. Step 3: Cross multiply
   1,290.86x = 1,938.57 × 961.89
4. Step 4: Simplify right side
   1,290.86x = 1,864,686.29
5. Step 5: Solve for x
   x = 1,864,686.29/1,290.86
6. Step 6: Final answer
   x = 1,444.53