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Finding the Fourth Proportional to 520.79, 781.18 and 212.58

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Solution

The fourth proportional to 520.79, 781.18 and 212.58 is: 318.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.79 : 781.18 = 212.58 : x
  2. Step 2: Convert to fraction form
    520.79/781.18 = 212.58/x
  3. Step 3: Cross multiply
    520.79x = 781.18 × 212.58
  4. Step 4: Simplify right side
    520.79x = 166,062.71
  5. Step 5: Solve for x
    x = 166,062.71/520.79
  6. Step 6: Final answer
    x = 318.87

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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.