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Finding the Fourth Proportional to 520.82, 780.60 and 398.72

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Solution

The fourth proportional to 520.82, 780.60 and 398.72 is: 597.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.82 : 780.60 = 398.72 : x
  2. Step 2: Convert to fraction form
    520.82/780.60 = 398.72/x
  3. Step 3: Cross multiply
    520.82x = 780.60 × 398.72
  4. Step 4: Simplify right side
    520.82x = 311,236.93
  5. Step 5: Solve for x
    x = 311,236.93/520.82
  6. Step 6: Final answer
    x = 597.60

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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.