Finding the Third Proportional to 21,120 and 31,800

Step by Step Solution

1. Step 1: Write the proportion equation
   21,120 : 31,800 = 31,800 : x
2. Step 2: Convert to fraction form
   21,120/31,800 = 31,800/x
3. Step 3: Cross multiply
   21,120x = 31,800 × 31,800
4. Step 4: Simplify right side
   21,120x = 1,011,240,000
5. Step 5: Solve for x
   x = 1,011,240,000/21,120
6. Step 6: Final answer
   x = 47,880.68