Finding the Third Proportional to 9,987 and 12,970.50

Step by Step Solution

1. Step 1: Write the proportion equation
   9,987 : 12,970.50 = 12,970.50 : x
2. Step 2: Convert to fraction form
   9,987/12,970.50 = 12,970.50/x
3. Step 3: Cross multiply
   9,987x = 12,970.50 × 12,970.50
4. Step 4: Simplify right side
   9,987x = 168,233,870.25
5. Step 5: Solve for x
   x = 168,233,870.25/9,987
6. Step 6: Final answer
   x = 16,845.29