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Finding the Fourth Proportional to 491.14, 678.24 and 420.79

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Solution

The fourth proportional to 491.14, 678.24 and 420.79 is: 581.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.14 : 678.24 = 420.79 : x
  2. Step 2: Convert to fraction form
    491.14/678.24 = 420.79/x
  3. Step 3: Cross multiply
    491.14x = 678.24 × 420.79
  4. Step 4: Simplify right side
    491.14x = 285,396.61
  5. Step 5: Solve for x
    x = 285,396.61/491.14
  6. Step 6: Final answer
    x = 581.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.