Finding the Third Proportional to 31,590 and 42,390

Step by Step Solution

1. Step 1: Write the proportion equation
   31,590 : 42,390 = 42,390 : x
2. Step 2: Convert to fraction form
   31,590/42,390 = 42,390/x
3. Step 3: Cross multiply
   31,590x = 42,390 × 42,390
4. Step 4: Simplify right side
   31,590x = 1,796,912,100
5. Step 5: Solve for x
   x = 1,796,912,100/31,590
6. Step 6: Final answer
   x = 56,882.31