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Finding the Fourth Proportional to 430.20, 645.30 and 213.69

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Solution

The fourth proportional to 430.20, 645.30 and 213.69 is: 320.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.20 : 645.30 = 213.69 : x
  2. Step 2: Convert to fraction form
    430.20/645.30 = 213.69/x
  3. Step 3: Cross multiply
    430.20x = 645.30 × 213.69
  4. Step 4: Simplify right side
    430.20x = 137,894.16
  5. Step 5: Solve for x
    x = 137,894.16/430.20
  6. Step 6: Final answer
    x = 320.54

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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.