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Finding the Third Proportional to 978 and 2,640

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Solution

The third proportional to 978 and 2,640 is: 7,126.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    978 : 2,640 = 2,640 : x
  2. Step 2: Convert to fraction form
    978/2,640 = 2,640/x
  3. Step 3: Cross multiply
    978x = 2,640 × 2,640
  4. Step 4: Simplify right side
    978x = 6,969,600
  5. Step 5: Solve for x
    x = 6,969,600/978
  6. Step 6: Final answer
    x = 7,126.38

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These problems maintain the same ratio (2.70) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.