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Finding the Fourth Proportional to 459.78, 689.81 and 285.87

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Solution

The fourth proportional to 459.78, 689.81 and 285.87 is: 428.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    459.78 : 689.81 = 285.87 : x
  2. Step 2: Convert to fraction form
    459.78/689.81 = 285.87/x
  3. Step 3: Cross multiply
    459.78x = 689.81 × 285.87
  4. Step 4: Simplify right side
    459.78x = 197,195.98
  5. Step 5: Solve for x
    x = 197,195.98/459.78
  6. Step 6: Final answer
    x = 428.89

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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.