Finding the Third Proportional to 21,240 and 31,131

Step by Step Solution

1. Step 1: Write the proportion equation
   21,240 : 31,131 = 31,131 : x
2. Step 2: Convert to fraction form
   21,240/31,131 = 31,131/x
3. Step 3: Cross multiply
   21,240x = 31,131 × 31,131
4. Step 4: Simplify right side
   21,240x = 969,139,161
5. Step 5: Solve for x
   x = 969,139,161/21,240
6. Step 6: Final answer
   x = 45,628.02