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Finding the Third Proportional to 278.34 and 431.39

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Solution

The third proportional to 278.34 and 431.39 is: 668.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.34 : 431.39 = 431.39 : x
  2. Step 2: Convert to fraction form
    278.34/431.39 = 431.39/x
  3. Step 3: Cross multiply
    278.34x = 431.39 × 431.39
  4. Step 4: Simplify right side
    278.34x = 186,097.87
  5. Step 5: Solve for x
    x = 186,097.87/278.34
  6. Step 6: Final answer
    x = 668.59

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.