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Finding the Fourth Proportional to 430.87, 645.21 and 213.88

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Solution

The fourth proportional to 430.87, 645.21 and 213.88 is: 320.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.87 : 645.21 = 213.88 : x
  2. Step 2: Convert to fraction form
    430.87/645.21 = 213.88/x
  3. Step 3: Cross multiply
    430.87x = 645.21 × 213.88
  4. Step 4: Simplify right side
    430.87x = 137,997.51
  5. Step 5: Solve for x
    x = 137,997.51/430.87
  6. Step 6: Final answer
    x = 320.28

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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.