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Finding the Fourth Proportional to 641.76, 885.16 and 420.88

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Solution

The fourth proportional to 641.76, 885.16 and 420.88 is: 580.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.76 : 885.16 = 420.88 : x
  2. Step 2: Convert to fraction form
    641.76/885.16 = 420.88/x
  3. Step 3: Cross multiply
    641.76x = 885.16 × 420.88
  4. Step 4: Simplify right side
    641.76x = 372,546.14
  5. Step 5: Solve for x
    x = 372,546.14/641.76
  6. Step 6: Final answer
    x = 580.51

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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.