Finding the Fourth Proportional to 1,987.30, 2,978.49 and 687.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,987.30 : 2,978.49 = 687.25 : x
2. Step 2: Convert to fraction form
   1,987.30/2,978.49 = 687.25/x
3. Step 3: Cross multiply
   1,987.30x = 2,978.49 × 687.25
4. Step 4: Simplify right side
   1,987.30x = 2,046,967.25
5. Step 5: Solve for x
   x = 2,046,967.25/1,987.30
6. Step 6: Final answer
   x = 1,030.02