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Finding the Fourth Proportional to 641.82, 885.58 and 420.39

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Solution

The fourth proportional to 641.82, 885.58 and 420.39 is: 580.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.82 : 885.58 = 420.39 : x
  2. Step 2: Convert to fraction form
    641.82/885.58 = 420.39/x
  3. Step 3: Cross multiply
    641.82x = 885.58 × 420.39
  4. Step 4: Simplify right side
    641.82x = 372,290.29
  5. Step 5: Solve for x
    x = 372,290.29/641.82
  6. Step 6: Final answer
    x = 580.05

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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.