Finding the Third Proportional to 380.81 and 820.69

Step by Step Solution

1. Step 1: Write the proportion equation
   380.81 : 820.69 = 820.69 : x
2. Step 2: Convert to fraction form
   380.81/820.69 = 820.69/x
3. Step 3: Cross multiply
   380.81x = 820.69 × 820.69
4. Step 4: Simplify right side
   380.81x = 673,527.97
5. Step 5: Solve for x
   x = 673,527.97/380.81
6. Step 6: Final answer
   x = 1,768.66