Finding the Third Proportional to 19,920 and 42,440

Step by Step Solution

1. Step 1: Write the proportion equation
   19,920 : 42,440 = 42,440 : x
2. Step 2: Convert to fraction form
   19,920/42,440 = 42,440/x
3. Step 3: Cross multiply
   19,920x = 42,440 × 42,440
4. Step 4: Simplify right side
   19,920x = 1,801,153,600
5. Step 5: Solve for x
   x = 1,801,153,600/19,920
6. Step 6: Final answer
   x = 90,419.36