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Finding the Fourth Proportional to 487.20, 672.20 and 280.20

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Solution

The fourth proportional to 487.20, 672.20 and 280.20 is: 386.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.20 : 672.20 = 280.20 : x
  2. Step 2: Convert to fraction form
    487.20/672.20 = 280.20/x
  3. Step 3: Cross multiply
    487.20x = 672.20 × 280.20
  4. Step 4: Simplify right side
    487.20x = 188,350.44
  5. Step 5: Solve for x
    x = 188,350.44/487.20
  6. Step 6: Final answer
    x = 386.60

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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.