Finding the Fourth Proportional to 1,390.39, 1,918.73 and 760.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.39 : 1,918.73 = 760.91 : x
2. Step 2: Convert to fraction form
   1,390.39/1,918.73 = 760.91/x
3. Step 3: Cross multiply
   1,390.39x = 1,918.73 × 760.91
4. Step 4: Simplify right side
   1,390.39x = 1,459,989.34
5. Step 5: Solve for x
   x = 1,459,989.34/1,390.39
6. Step 6: Final answer
   x = 1,050.06