Finding the Third Proportional to 9,990 and 14,788.50

Step by Step Solution

1. Step 1: Write the proportion equation
   9,990 : 14,788.50 = 14,788.50 : x
2. Step 2: Convert to fraction form
   9,990/14,788.50 = 14,788.50/x
3. Step 3: Cross multiply
   9,990x = 14,788.50 × 14,788.50
4. Step 4: Simplify right side
   9,990x = 218,699,732.25
5. Step 5: Solve for x
   x = 218,699,732.25/9,990
6. Step 6: Final answer
   x = 21,891.87