Finding the Third Proportional to 21,870 and 42,342.75

Step by Step Solution

1. Step 1: Write the proportion equation
   21,870 : 42,342.75 = 42,342.75 : x
2. Step 2: Convert to fraction form
   21,870/42,342.75 = 42,342.75/x
3. Step 3: Cross multiply
   21,870x = 42,342.75 × 42,342.75
4. Step 4: Simplify right side
   21,870x = 1,792,908,477.56
5. Step 5: Solve for x
   x = 1,792,908,477.56/21,870
6. Step 6: Final answer
   x = 81,980.27