Finding the Fourth Proportional to 1,986.98, 2,978.35 and 1,256.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,986.98 : 2,978.35 = 1,256.77 : x
2. Step 2: Convert to fraction form
   1,986.98/2,978.35 = 1,256.77/x
3. Step 3: Cross multiply
   1,986.98x = 2,978.35 × 1,256.77
4. Step 4: Simplify right side
   1,986.98x = 3,743,090.34
5. Step 5: Solve for x
   x = 3,743,090.34/1,986.98
6. Step 6: Final answer
   x = 1,883.81