Finding the Fourth Proportional to 1,290.42, 1,780.55 and 723.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.42 : 1,780.55 = 723.24 : x
2. Step 2: Convert to fraction form
   1,290.42/1,780.55 = 723.24/x
3. Step 3: Cross multiply
   1,290.42x = 1,780.55 × 723.24
4. Step 4: Simplify right side
   1,290.42x = 1,287,761.37
5. Step 5: Solve for x
   x = 1,287,761.37/1,290.42
6. Step 6: Final answer
   x = 997.94