Finding the Third Proportional to 21,168 and 30,120

Step by Step Solution

1. Step 1: Write the proportion equation
   21,168 : 30,120 = 30,120 : x
2. Step 2: Convert to fraction form
   21,168/30,120 = 30,120/x
3. Step 3: Cross multiply
   21,168x = 30,120 × 30,120
4. Step 4: Simplify right side
   21,168x = 907,214,400
5. Step 5: Solve for x
   x = 907,214,400/21,168
6. Step 6: Final answer
   x = 42,857.82