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Finding the Fourth Proportional to 645.21, 890.42 and 423.99

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Solution

The fourth proportional to 645.21, 890.42 and 423.99 is: 585.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.21 : 890.42 = 423.99 : x
  2. Step 2: Convert to fraction form
    645.21/890.42 = 423.99/x
  3. Step 3: Cross multiply
    645.21x = 890.42 × 423.99
  4. Step 4: Simplify right side
    645.21x = 377,527.06
  5. Step 5: Solve for x
    x = 377,527.06/645.21
  6. Step 6: Final answer
    x = 585.12

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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.