Finding the Fourth Proportional to 1,290.15, 1,780.61 and 730.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.15 : 1,780.61 = 730.68 : x
2. Step 2: Convert to fraction form
   1,290.15/1,780.61 = 730.68/x
3. Step 3: Cross multiply
   1,290.15x = 1,780.61 × 730.68
4. Step 4: Simplify right side
   1,290.15x = 1,301,045.78
5. Step 5: Solve for x
   x = 1,301,045.78/1,290.15
6. Step 6: Final answer
   x = 1,008.45