Finding the Third Proportional to 405.84 and 871.78

Step by Step Solution

1. Step 1: Write the proportion equation
   405.84 : 871.78 = 871.78 : x
2. Step 2: Convert to fraction form
   405.84/871.78 = 871.78/x
3. Step 3: Cross multiply
   405.84x = 871.78 × 871.78
4. Step 4: Simplify right side
   405.84x = 760,002.55
5. Step 5: Solve for x
   x = 760,002.55/405.84
6. Step 6: Final answer
   x = 1,872.65