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Finding the Third Proportional to 309.38 and 686.63

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Solution

The third proportional to 309.38 and 686.63 is: 1,523.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.38 : 686.63 = 686.63 : x
  2. Step 2: Convert to fraction form
    309.38/686.63 = 686.63/x
  3. Step 3: Cross multiply
    309.38x = 686.63 × 686.63
  4. Step 4: Simplify right side
    309.38x = 471,453.89
  5. Step 5: Solve for x
    x = 471,453.89/309.38
  6. Step 6: Final answer
    x = 1,523.89

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Why These Related Problems?

These problems maintain the same ratio (2.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.