Finding the Third Proportional to 13,872 and 31,380

Step by Step Solution

1. Step 1: Write the proportion equation
   13,872 : 31,380 = 31,380 : x
2. Step 2: Convert to fraction form
   13,872/31,380 = 31,380/x
3. Step 3: Cross multiply
   13,872x = 31,380 × 31,380
4. Step 4: Simplify right side
   13,872x = 984,704,400
5. Step 5: Solve for x
   x = 984,704,400/13,872
6. Step 6: Final answer
   x = 70,985.03