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Finding the Fourth Proportional to 979.76, 1,351.89 and 665.28

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Solution

The fourth proportional to 979.76, 1,351.89 and 665.28 is: 917.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.76 : 1,351.89 = 665.28 : x
  2. Step 2: Convert to fraction form
    979.76/1,351.89 = 665.28/x
  3. Step 3: Cross multiply
    979.76x = 1,351.89 × 665.28
  4. Step 4: Simplify right side
    979.76x = 899,385.38
  5. Step 5: Solve for x
    x = 899,385.38/979.76
  6. Step 6: Final answer
    x = 917.96

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.