Finding the Third Proportional to 19,890 and 42,144

Step by Step Solution

1. Step 1: Write the proportion equation
   19,890 : 42,144 = 42,144 : x
2. Step 2: Convert to fraction form
   19,890/42,144 = 42,144/x
3. Step 3: Cross multiply
   19,890x = 42,144 × 42,144
4. Step 4: Simplify right side
   19,890x = 1,776,116,736
5. Step 5: Solve for x
   x = 1,776,116,736/19,890
6. Step 6: Final answer
   x = 89,296.97