Finding the Fourth Proportional to 1,290.34, 1,780.72 and 730.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.34 : 1,780.72 = 730.88 : x
2. Step 2: Convert to fraction form
   1,290.34/1,780.72 = 730.88/x
3. Step 3: Cross multiply
   1,290.34x = 1,780.72 × 730.88
4. Step 4: Simplify right side
   1,290.34x = 1,301,483.73
5. Step 5: Solve for x
   x = 1,301,483.73/1,290.34
6. Step 6: Final answer
   x = 1,008.64