Finding the Fourth Proportional to 2,141.28, 3,209.76 and 987.84

Step by Step Solution

1. Step 1: Write the proportion equation
   2,141.28 : 3,209.76 = 987.84 : x
2. Step 2: Convert to fraction form
   2,141.28/3,209.76 = 987.84/x
3. Step 3: Cross multiply
   2,141.28x = 3,209.76 × 987.84
4. Step 4: Simplify right side
   2,141.28x = 3,170,729.32
5. Step 5: Solve for x
   x = 3,170,729.32/2,141.28
6. Step 6: Final answer
   x = 1,480.76