Finding the Third Proportional to 20,870 and 31,490

Step by Step Solution

1. Step 1: Write the proportion equation
   20,870 : 31,490 = 31,490 : x
2. Step 2: Convert to fraction form
   20,870/31,490 = 31,490/x
3. Step 3: Cross multiply
   20,870x = 31,490 × 31,490
4. Step 4: Simplify right side
   20,870x = 991,620,100
5. Step 5: Solve for x
   x = 991,620,100/20,870
6. Step 6: Final answer
   x = 47,514.14