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Finding the Fourth Proportional to 520.80, 781.17 and 212.57

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Solution

The fourth proportional to 520.80, 781.17 and 212.57 is: 318.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.80 : 781.17 = 212.57 : x
  2. Step 2: Convert to fraction form
    520.80/781.17 = 212.57/x
  3. Step 3: Cross multiply
    520.80x = 781.17 × 212.57
  4. Step 4: Simplify right side
    520.80x = 166,053.31
  5. Step 5: Solve for x
    x = 166,053.31/520.80
  6. Step 6: Final answer
    x = 318.84

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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.