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Finding the Fourth Proportional to 520.81, 780.19 and 315.47

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Solution

The fourth proportional to 520.81, 780.19 and 315.47 is: 472.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.81 : 780.19 = 315.47 : x
  2. Step 2: Convert to fraction form
    520.81/780.19 = 315.47/x
  3. Step 3: Cross multiply
    520.81x = 780.19 × 315.47
  4. Step 4: Simplify right side
    520.81x = 246,126.54
  5. Step 5: Solve for x
    x = 246,126.54/520.81
  6. Step 6: Final answer
    x = 472.58

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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.