Finding the Third Proportional to 390.38 and 842.63

Step by Step Solution

1. Step 1: Write the proportion equation
   390.38 : 842.63 = 842.63 : x
2. Step 2: Convert to fraction form
   390.38/842.63 = 842.63/x
3. Step 3: Cross multiply
   390.38x = 842.63 × 842.63
4. Step 4: Simplify right side
   390.38x = 710,016.89
5. Step 5: Solve for x
   x = 710,016.89/390.38
6. Step 6: Final answer
   x = 1,818.81