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Finding the Fourth Proportional to 521.10, 781.70 and 212.90

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Solution

The fourth proportional to 521.10, 781.70 and 212.90 is: 319.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.10 : 781.70 = 212.90 : x
  2. Step 2: Convert to fraction form
    521.10/781.70 = 212.90/x
  3. Step 3: Cross multiply
    521.10x = 781.70 × 212.90
  4. Step 4: Simplify right side
    521.10x = 166,427.65
  5. Step 5: Solve for x
    x = 166,427.65/521.10
  6. Step 6: Final answer
    x = 319.38

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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.