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Finding the Fourth Proportional to 516.78, 772.18 and 390.87

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Solution

The fourth proportional to 516.78, 772.18 and 390.87 is: 584.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    516.78 : 772.18 = 390.87 : x
  2. Step 2: Convert to fraction form
    516.78/772.18 = 390.87/x
  3. Step 3: Cross multiply
    516.78x = 772.18 × 390.87
  4. Step 4: Simplify right side
    516.78x = 301,816.18
  5. Step 5: Solve for x
    x = 301,816.18/516.78
  6. Step 6: Final answer
    x = 584.04

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.