Finding the Third Proportional to 311.34 and 422.72

Step by Step Solution

1. Step 1: Write the proportion equation
   311.34 : 422.72 = 422.72 : x
2. Step 2: Convert to fraction form
   311.34/422.72 = 422.72/x
3. Step 3: Cross multiply
   311.34x = 422.72 × 422.72
4. Step 4: Simplify right side
   311.34x = 178,691.14
5. Step 5: Solve for x
   x = 178,691.14/311.34
6. Step 6: Final answer
   x = 573.94