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Finding the Fourth Proportional to 979.20, 1,470.48 and 869.76

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Solution

The fourth proportional to 979.20, 1,470.48 and 869.76 is: 1,306.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.20 : 1,470.48 = 869.76 : x
  2. Step 2: Convert to fraction form
    979.20/1,470.48 = 869.76/x
  3. Step 3: Cross multiply
    979.20x = 1,470.48 × 869.76
  4. Step 4: Simplify right side
    979.20x = 1,278,964.68
  5. Step 5: Solve for x
    x = 1,278,964.68/979.20
  6. Step 6: Final answer
    x = 1,306.13

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.