Finding the Third Proportional to 12,769 and 21,178

Step by Step Solution

1. Step 1: Write the proportion equation
   12,769 : 21,178 = 21,178 : x
2. Step 2: Convert to fraction form
   12,769/21,178 = 21,178/x
3. Step 3: Cross multiply
   12,769x = 21,178 × 21,178
4. Step 4: Simplify right side
   12,769x = 448,507,684
5. Step 5: Solve for x
   x = 448,507,684/12,769
6. Step 6: Final answer
   x = 35,124.73