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Finding the Fourth Proportional to 430.42, 645.81 and 213.88

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Solution

The fourth proportional to 430.42, 645.81 and 213.88 is: 320.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.42 : 645.81 = 213.88 : x
  2. Step 2: Convert to fraction form
    430.42/645.81 = 213.88/x
  3. Step 3: Cross multiply
    430.42x = 645.81 × 213.88
  4. Step 4: Simplify right side
    430.42x = 138,125.84
  5. Step 5: Solve for x
    x = 138,125.84/430.42
  6. Step 6: Final answer
    x = 320.91

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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.