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Finding the Fourth Proportional to 712.80, 979.20 and 581.40

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Solution

The fourth proportional to 712.80, 979.20 and 581.40 is: 798.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.80 : 979.20 = 581.40 : x
  2. Step 2: Convert to fraction form
    712.80/979.20 = 581.40/x
  3. Step 3: Cross multiply
    712.80x = 979.20 × 581.40
  4. Step 4: Simplify right side
    712.80x = 569,306.88
  5. Step 5: Solve for x
    x = 569,306.88/712.80
  6. Step 6: Final answer
    x = 798.69

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.