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Finding the Fourth Proportional to 641.53, 885 and 420.27

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Solution

The fourth proportional to 641.53, 885 and 420.27 is: 579.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.53 : 885 = 420.27 : x
  2. Step 2: Convert to fraction form
    641.53/885 = 420.27/x
  3. Step 3: Cross multiply
    641.53x = 885 × 420.27
  4. Step 4: Simplify right side
    641.53x = 371,938.95
  5. Step 5: Solve for x
    x = 371,938.95/641.53
  6. Step 6: Final answer
    x = 579.77

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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.