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Finding the Fourth Proportional to 645.75, 969.09 and 280.80

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Solution

The fourth proportional to 645.75, 969.09 and 280.80 is: 421.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.75 : 969.09 = 280.80 : x
  2. Step 2: Convert to fraction form
    645.75/969.09 = 280.80/x
  3. Step 3: Cross multiply
    645.75x = 969.09 × 280.80
  4. Step 4: Simplify right side
    645.75x = 272,120.47
  5. Step 5: Solve for x
    x = 272,120.47/645.75
  6. Step 6: Final answer
    x = 421.40

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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.