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Finding the Fourth Proportional to 520.80, 780.96 and 212.55

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Solution

The fourth proportional to 520.80, 780.96 and 212.55 is: 318.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.80 : 780.96 = 212.55 : x
  2. Step 2: Convert to fraction form
    520.80/780.96 = 212.55/x
  3. Step 3: Cross multiply
    520.80x = 780.96 × 212.55
  4. Step 4: Simplify right side
    520.80x = 165,993.05
  5. Step 5: Solve for x
    x = 165,993.05/520.80
  6. Step 6: Final answer
    x = 318.73

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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.