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Finding the Third Proportional to 30.78 and 65.09

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Solution

The third proportional to 30.78 and 65.09 is: 137.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.78 : 65.09 = 65.09 : x
  2. Step 2: Convert to fraction form
    30.78/65.09 = 65.09/x
  3. Step 3: Cross multiply
    30.78x = 65.09 × 65.09
  4. Step 4: Simplify right side
    30.78x = 4,237.20
  5. Step 5: Solve for x
    x = 4,237.20/30.78
  6. Step 6: Final answer
    x = 137.66

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Why These Related Problems?

These problems maintain the same ratio (2.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.