Finding the Third Proportional to 7,857 and 12,499.50

Step by Step Solution

1. Step 1: Write the proportion equation
   7,857 : 12,499.50 = 12,499.50 : x
2. Step 2: Convert to fraction form
   7,857/12,499.50 = 12,499.50/x
3. Step 3: Cross multiply
   7,857x = 12,499.50 × 12,499.50
4. Step 4: Simplify right side
   7,857x = 156,237,500.25
5. Step 5: Solve for x
   x = 156,237,500.25/7,857
6. Step 6: Final answer
   x = 19,885.13