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Finding the Fourth Proportional to 420.75, 630.30 and 214.71

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Solution

The fourth proportional to 420.75, 630.30 and 214.71 is: 321.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.75 : 630.30 = 214.71 : x
  2. Step 2: Convert to fraction form
    420.75/630.30 = 214.71/x
  3. Step 3: Cross multiply
    420.75x = 630.30 × 214.71
  4. Step 4: Simplify right side
    420.75x = 135,331.71
  5. Step 5: Solve for x
    x = 135,331.71/420.75
  6. Step 6: Final answer
    x = 321.64

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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.