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Finding the Fourth Proportional to 641.40, 884.90 and 420.47

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Solution

The fourth proportional to 641.40, 884.90 and 420.47 is: 580.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.40 : 884.90 = 420.47 : x
  2. Step 2: Convert to fraction form
    641.40/884.90 = 420.47/x
  3. Step 3: Cross multiply
    641.40x = 884.90 × 420.47
  4. Step 4: Simplify right side
    641.40x = 372,074.01
  5. Step 5: Solve for x
    x = 372,074.01/641.40
  6. Step 6: Final answer
    x = 580.10

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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.