Finding the Third Proportional to 17,872 and 42,128

Step by Step Solution

1. Step 1: Write the proportion equation
   17,872 : 42,128 = 42,128 : x
2. Step 2: Convert to fraction form
   17,872/42,128 = 42,128/x
3. Step 3: Cross multiply
   17,872x = 42,128 × 42,128
4. Step 4: Simplify right side
   17,872x = 1,774,768,384
5. Step 5: Solve for x
   x = 1,774,768,384/17,872
6. Step 6: Final answer
   x = 99,304.41