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Finding the Fourth Proportional to 643.89, 888.36 and 381.86

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Solution

The fourth proportional to 643.89, 888.36 and 381.86 is: 526.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.89 : 888.36 = 381.86 : x
  2. Step 2: Convert to fraction form
    643.89/888.36 = 381.86/x
  3. Step 3: Cross multiply
    643.89x = 888.36 × 381.86
  4. Step 4: Simplify right side
    643.89x = 339,224.71
  5. Step 5: Solve for x
    x = 339,224.71/643.89
  6. Step 6: Final answer
    x = 526.84

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Double scale
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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.