Finding the Third Proportional to 392.72 and 853.69

Step by Step Solution

1. Step 1: Write the proportion equation
   392.72 : 853.69 = 853.69 : x
2. Step 2: Convert to fraction form
   392.72/853.69 = 853.69/x
3. Step 3: Cross multiply
   392.72x = 853.69 × 853.69
4. Step 4: Simplify right side
   392.72x = 728,782.35
5. Step 5: Solve for x
   x = 728,782.35/392.72
6. Step 6: Final answer
   x = 1,855.74