Finding the Fourth Proportional to 1,290.80, 1,927.46 and 1,013.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.80 : 1,927.46 = 1,013.78 : x
2. Step 2: Convert to fraction form
   1,290.80/1,927.46 = 1,013.78/x
3. Step 3: Cross multiply
   1,290.80x = 1,927.46 × 1,013.78
4. Step 4: Simplify right side
   1,290.80x = 1,954,005.69
5. Step 5: Solve for x
   x = 1,954,005.69/1,290.80
6. Step 6: Final answer
   x = 1,513.80