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Finding the Fourth Proportional to 520.86, 781.49 and 212.80

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Solution

The fourth proportional to 520.86, 781.49 and 212.80 is: 319.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.86 : 781.49 = 212.80 : x
  2. Step 2: Convert to fraction form
    520.86/781.49 = 212.80/x
  3. Step 3: Cross multiply
    520.86x = 781.49 × 212.80
  4. Step 4: Simplify right side
    520.86x = 166,300.01
  5. Step 5: Solve for x
    x = 166,300.01/520.86
  6. Step 6: Final answer
    x = 319.28

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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.