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Finding the Fourth Proportional to 853.39, 1,279.80 and 414.40

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Solution

The fourth proportional to 853.39, 1,279.80 and 414.40 is: 621.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.39 : 1,279.80 = 414.40 : x
  2. Step 2: Convert to fraction form
    853.39/1,279.80 = 414.40/x
  3. Step 3: Cross multiply
    853.39x = 1,279.80 × 414.40
  4. Step 4: Simplify right side
    853.39x = 530,349.12
  5. Step 5: Solve for x
    x = 530,349.12/853.39
  6. Step 6: Final answer
    x = 621.46

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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.