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Finding the Fourth Proportional to 427.40, 640.82 and 289.70

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Solution

The fourth proportional to 427.40, 640.82 and 289.70 is: 434.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.40 : 640.82 = 289.70 : x
  2. Step 2: Convert to fraction form
    427.40/640.82 = 289.70/x
  3. Step 3: Cross multiply
    427.40x = 640.82 × 289.70
  4. Step 4: Simplify right side
    427.40x = 185,645.55
  5. Step 5: Solve for x
    x = 185,645.55/427.40
  6. Step 6: Final answer
    x = 434.36

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.