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Finding the Fourth Proportional to 421.47, 631.89 and 213.10

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Solution

The fourth proportional to 421.47, 631.89 and 213.10 is: 319.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.47 : 631.89 = 213.10 : x
  2. Step 2: Convert to fraction form
    421.47/631.89 = 213.10/x
  3. Step 3: Cross multiply
    421.47x = 631.89 × 213.10
  4. Step 4: Simplify right side
    421.47x = 134,654.18
  5. Step 5: Solve for x
    x = 134,654.18/421.47
  6. Step 6: Final answer
    x = 319.49

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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.