Finding the Fourth Proportional to 1,290.25, 1,780.55 and 700.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.25 : 1,780.55 = 700.79 : x
2. Step 2: Convert to fraction form
   1,290.25/1,780.55 = 700.79/x
3. Step 3: Cross multiply
   1,290.25x = 1,780.55 × 700.79
4. Step 4: Simplify right side
   1,290.25x = 1,247,791.63
5. Step 5: Solve for x
   x = 1,247,791.63/1,290.25
6. Step 6: Final answer
   x = 967.09