Finding the Third Proportional to 12,811.50 and 21,165.75

Step by Step Solution

1. Step 1: Write the proportion equation
   12,811.50 : 21,165.75 = 21,165.75 : x
2. Step 2: Convert to fraction form
   12,811.50/21,165.75 = 21,165.75/x
3. Step 3: Cross multiply
   12,811.50x = 21,165.75 × 21,165.75
4. Step 4: Simplify right side
   12,811.50x = 447,988,973.06
5. Step 5: Solve for x
   x = 447,988,973.06/12,811.50
6. Step 6: Final answer
   x = 34,967.72