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Finding the Fourth Proportional to 645.42, 890.69 and 383.61

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Solution

The fourth proportional to 645.42, 890.69 and 383.61 is: 529.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.42 : 890.69 = 383.61 : x
  2. Step 2: Convert to fraction form
    645.42/890.69 = 383.61/x
  3. Step 3: Cross multiply
    645.42x = 890.69 × 383.61
  4. Step 4: Simplify right side
    645.42x = 341,677.59
  5. Step 5: Solve for x
    x = 341,677.59/645.42
  6. Step 6: Final answer
    x = 529.39

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Double scale
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1.5x scale

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.