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Finding the Fourth Proportional to 643.40, 887.65 and 422.47

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Solution

The fourth proportional to 643.40, 887.65 and 422.47 is: 582.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.40 : 887.65 = 422.47 : x
  2. Step 2: Convert to fraction form
    643.40/887.65 = 422.47/x
  3. Step 3: Cross multiply
    643.40x = 887.65 × 422.47
  4. Step 4: Simplify right side
    643.40x = 375,005.50
  5. Step 5: Solve for x
    x = 375,005.50/643.40
  6. Step 6: Final answer
    x = 582.85

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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.