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Finding the Third Proportional to 311.75 and 421.75

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Solution

The third proportional to 311.75 and 421.75 is: 570.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.75 : 421.75 = 421.75 : x
  2. Step 2: Convert to fraction form
    311.75/421.75 = 421.75/x
  3. Step 3: Cross multiply
    311.75x = 421.75 × 421.75
  4. Step 4: Simplify right side
    311.75x = 177,873.06
  5. Step 5: Solve for x
    x = 177,873.06/311.75
  6. Step 6: Final answer
    x = 570.56

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Why These Related Problems?

These problems maintain the same ratio (1.35) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.