Finding the Fourth Proportional to 2,139.75, 2,953.40 and 1,208.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.75 : 2,953.40 = 1,208.79 : x
2. Step 2: Convert to fraction form
   2,139.75/2,953.40 = 1,208.79/x
3. Step 3: Cross multiply
   2,139.75x = 2,953.40 × 1,208.79
4. Step 4: Simplify right side
   2,139.75x = 3,570,034.34
5. Step 5: Solve for x
   x = 3,570,034.34/2,139.75
6. Step 6: Final answer
   x = 1,668.44