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Finding the Fourth Proportional to 521.80, 781.90 and 440.20

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Solution

The fourth proportional to 521.80, 781.90 and 440.20 is: 659.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.80 : 781.90 = 440.20 : x
  2. Step 2: Convert to fraction form
    521.80/781.90 = 440.20/x
  3. Step 3: Cross multiply
    521.80x = 781.90 × 440.20
  4. Step 4: Simplify right side
    521.80x = 344,192.38
  5. Step 5: Solve for x
    x = 344,192.38/521.80
  6. Step 6: Final answer
    x = 659.63

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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.