Finding the Fourth Proportional to 10,912.56, 16,368.72 and 3,987

Step by Step Solution

1. Step 1: Write the proportion equation
   10,912.56 : 16,368.72 = 3,987 : x
2. Step 2: Convert to fraction form
   10,912.56/16,368.72 = 3,987/x
3. Step 3: Cross multiply
   10,912.56x = 16,368.72 × 3,987
4. Step 4: Simplify right side
   10,912.56x = 65,262,086.64
5. Step 5: Solve for x
   x = 65,262,086.64/10,912.56
6. Step 6: Final answer
   x = 5,980.46