Finding the Third Proportional to 3,987.75 and 8,731.50

Step by Step Solution

1. Step 1: Write the proportion equation
   3,987.75 : 8,731.50 = 8,731.50 : x
2. Step 2: Convert to fraction form
   3,987.75/8,731.50 = 8,731.50/x
3. Step 3: Cross multiply
   3,987.75x = 8,731.50 × 8,731.50
4. Step 4: Simplify right side
   3,987.75x = 76,239,092.25
5. Step 5: Solve for x
   x = 76,239,092.25/3,987.75
6. Step 6: Final answer
   x = 19,118.32