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Finding the Fourth Proportional to 645.39, 890.66 and 379.85

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Solution

The fourth proportional to 645.39, 890.66 and 379.85 is: 524.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.39 : 890.66 = 379.85 : x
  2. Step 2: Convert to fraction form
    645.39/890.66 = 379.85/x
  3. Step 3: Cross multiply
    645.39x = 890.66 × 379.85
  4. Step 4: Simplify right side
    645.39x = 338,310.85
  5. Step 5: Solve for x
    x = 338,310.85/645.39
  6. Step 6: Final answer
    x = 524.20

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.