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Finding the Third Proportional to 309.56 and 643.13

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Solution

The third proportional to 309.56 and 643.13 is: 1,336.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.56 : 643.13 = 643.13 : x
  2. Step 2: Convert to fraction form
    309.56/643.13 = 643.13/x
  3. Step 3: Cross multiply
    309.56x = 643.13 × 643.13
  4. Step 4: Simplify right side
    309.56x = 413,609.77
  5. Step 5: Solve for x
    x = 413,609.77/309.56
  6. Step 6: Final answer
    x = 1,336.11

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Why These Related Problems?

These problems maintain the same ratio (2.08) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.