Finding the Fourth Proportional to 1,290.96, 1,780.56 and 1,116

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.96 : 1,780.56 = 1,116 : x
2. Step 2: Convert to fraction form
   1,290.96/1,780.56 = 1,116/x
3. Step 3: Cross multiply
   1,290.96x = 1,780.56 × 1,116
4. Step 4: Simplify right side
   1,290.96x = 1,987,104.96
5. Step 5: Solve for x
   x = 1,987,104.96/1,290.96
6. Step 6: Final answer
   x = 1,539.25