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Finding the Third Proportional to 39 and 70.75

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Solution

The third proportional to 39 and 70.75 is: 128.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    39 : 70.75 = 70.75 : x
  2. Step 2: Convert to fraction form
    39/70.75 = 70.75/x
  3. Step 3: Cross multiply
    39x = 70.75 × 70.75
  4. Step 4: Simplify right side
    39x = 5,005.56
  5. Step 5: Solve for x
    x = 5,005.56/39
  6. Step 6: Final answer
    x = 128.35

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Why These Related Problems?

These problems maintain the same ratio (1.81) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.