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Finding the Fourth Proportional to 499.20, 687.84 and 421.44

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Solution

The fourth proportional to 499.20, 687.84 and 421.44 is: 580.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.20 : 687.84 = 421.44 : x
  2. Step 2: Convert to fraction form
    499.20/687.84 = 421.44/x
  3. Step 3: Cross multiply
    499.20x = 687.84 × 421.44
  4. Step 4: Simplify right side
    499.20x = 289,883.29
  5. Step 5: Solve for x
    x = 289,883.29/499.20
  6. Step 6: Final answer
    x = 580.70

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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.