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Finding the Fourth Proportional to 430.50, 645.72 and 213.90

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Solution

The fourth proportional to 430.50, 645.72 and 213.90 is: 320.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.50 : 645.72 = 213.90 : x
  2. Step 2: Convert to fraction form
    430.50/645.72 = 213.90/x
  3. Step 3: Cross multiply
    430.50x = 645.72 × 213.90
  4. Step 4: Simplify right side
    430.50x = 138,119.51
  5. Step 5: Solve for x
    x = 138,119.51/430.50
  6. Step 6: Final answer
    x = 320.84

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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.