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Finding the Fourth Proportional to 645.20, 970.20 and 539.60

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Solution

The fourth proportional to 645.20, 970.20 and 539.60 is: 811.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.20 : 970.20 = 539.60 : x
  2. Step 2: Convert to fraction form
    645.20/970.20 = 539.60/x
  3. Step 3: Cross multiply
    645.20x = 970.20 × 539.60
  4. Step 4: Simplify right side
    645.20x = 523,519.92
  5. Step 5: Solve for x
    x = 523,519.92/645.20
  6. Step 6: Final answer
    x = 811.41

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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.