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Finding the Fourth Proportional to 419.20, 628.80 and 289.60

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Solution

The fourth proportional to 419.20, 628.80 and 289.60 is: 434.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.20 : 628.80 = 289.60 : x
  2. Step 2: Convert to fraction form
    419.20/628.80 = 289.60/x
  3. Step 3: Cross multiply
    419.20x = 628.80 × 289.60
  4. Step 4: Simplify right side
    419.20x = 182,100.48
  5. Step 5: Solve for x
    x = 182,100.48/419.20
  6. Step 6: Final answer
    x = 434.40

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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.