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Finding the Fourth Proportional to 979.87, 1,470.21 and 459.49

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Solution

The fourth proportional to 979.87, 1,470.21 and 459.49 is: 689.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.87 : 1,470.21 = 459.49 : x
  2. Step 2: Convert to fraction form
    979.87/1,470.21 = 459.49/x
  3. Step 3: Cross multiply
    979.87x = 1,470.21 × 459.49
  4. Step 4: Simplify right side
    979.87x = 675,546.79
  5. Step 5: Solve for x
    x = 675,546.79/979.87
  6. Step 6: Final answer
    x = 689.42

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1.5x scale

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.