Finding the Fourth Proportional to 1,390.25, 1,918.55 and 760.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.25 : 1,918.55 = 760.79 : x
2. Step 2: Convert to fraction form
   1,390.25/1,918.55 = 760.79/x
3. Step 3: Cross multiply
   1,390.25x = 1,918.55 × 760.79
4. Step 4: Simplify right side
   1,390.25x = 1,459,613.65
5. Step 5: Solve for x
   x = 1,459,613.65/1,390.25
6. Step 6: Final answer
   x = 1,049.89