Finding the Fourth Proportional to 1,647.72, 2,469.40 and 987.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,647.72 : 2,469.40 = 987.47 : x
2. Step 2: Convert to fraction form
   1,647.72/2,469.40 = 987.47/x
3. Step 3: Cross multiply
   1,647.72x = 2,469.40 × 987.47
4. Step 4: Simplify right side
   1,647.72x = 2,438,443.60
5. Step 5: Solve for x
   x = 2,438,443.60/1,647.72
6. Step 6: Final answer
   x = 1,479.89