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Finding the Fourth Proportional to 853.29, 1,279.53 and 390.69

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Solution

The fourth proportional to 853.29, 1,279.53 and 390.69 is: 585.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.29 : 1,279.53 = 390.69 : x
  2. Step 2: Convert to fraction form
    853.29/1,279.53 = 390.69/x
  3. Step 3: Cross multiply
    853.29x = 1,279.53 × 390.69
  4. Step 4: Simplify right side
    853.29x = 499,899.58
  5. Step 5: Solve for x
    x = 499,899.58/853.29
  6. Step 6: Final answer
    x = 585.85

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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.