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Finding the Fourth Proportional to 521.70, 781.87 and 213.19

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Solution

The fourth proportional to 521.70, 781.87 and 213.19 is: 319.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.70 : 781.87 = 213.19 : x
  2. Step 2: Convert to fraction form
    521.70/781.87 = 213.19/x
  3. Step 3: Cross multiply
    521.70x = 781.87 × 213.19
  4. Step 4: Simplify right side
    521.70x = 166,684.38
  5. Step 5: Solve for x
    x = 166,684.38/521.70
  6. Step 6: Final answer
    x = 319.50

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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.