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Finding the Fourth Proportional to 487.28, 730.80 and 213.20

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Solution

The fourth proportional to 487.28, 730.80 and 213.20 is: 319.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.28 : 730.80 = 213.20 : x
  2. Step 2: Convert to fraction form
    487.28/730.80 = 213.20/x
  3. Step 3: Cross multiply
    487.28x = 730.80 × 213.20
  4. Step 4: Simplify right side
    487.28x = 155,806.56
  5. Step 5: Solve for x
    x = 155,806.56/487.28
  6. Step 6: Final answer
    x = 319.75

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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.