Finding the Fourth Proportional to 1,985.69, 2,978.51 and 687.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,985.69 : 2,978.51 = 687.16 : x
2. Step 2: Convert to fraction form
   1,985.69/2,978.51 = 687.16/x
3. Step 3: Cross multiply
   1,985.69x = 2,978.51 × 687.16
4. Step 4: Simplify right side
   1,985.69x = 2,046,707.20
5. Step 5: Solve for x
   x = 2,046,707.20/1,985.69
6. Step 6: Final answer
   x = 1,030.73