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Finding the Fourth Proportional to 420.30, 630.39 and 214.65

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Solution

The fourth proportional to 420.30, 630.39 and 214.65 is: 321.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.30 : 630.39 = 214.65 : x
  2. Step 2: Convert to fraction form
    420.30/630.39 = 214.65/x
  3. Step 3: Cross multiply
    420.30x = 630.39 × 214.65
  4. Step 4: Simplify right side
    420.30x = 135,313.21
  5. Step 5: Solve for x
    x = 135,313.21/420.30
  6. Step 6: Final answer
    x = 321.94

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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.