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Finding the Fourth Proportional to 645.69, 891.56 and 397.13

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Solution

The fourth proportional to 645.69, 891.56 and 397.13 is: 548.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.69 : 891.56 = 397.13 : x
  2. Step 2: Convert to fraction form
    645.69/891.56 = 397.13/x
  3. Step 3: Cross multiply
    645.69x = 891.56 × 397.13
  4. Step 4: Simplify right side
    645.69x = 354,058.78
  5. Step 5: Solve for x
    x = 354,058.78/645.69
  6. Step 6: Final answer
    x = 548.34

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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.