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Finding the Fourth Proportional to 520.38, 780.55 and 212.15

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Solution

The fourth proportional to 520.38, 780.55 and 212.15 is: 318.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.38 : 780.55 = 212.15 : x
  2. Step 2: Convert to fraction form
    520.38/780.55 = 212.15/x
  3. Step 3: Cross multiply
    520.38x = 780.55 × 212.15
  4. Step 4: Simplify right side
    520.38x = 165,589.25
  5. Step 5: Solve for x
    x = 165,589.25/520.38
  6. Step 6: Final answer
    x = 318.21

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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.