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Finding the Fourth Proportional to 645.10, 890.21 and 423.65

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Solution

The fourth proportional to 645.10, 890.21 and 423.65 is: 584.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.10 : 890.21 = 423.65 : x
  2. Step 2: Convert to fraction form
    645.10/890.21 = 423.65/x
  3. Step 3: Cross multiply
    645.10x = 890.21 × 423.65
  4. Step 4: Simplify right side
    645.10x = 377,140.75
  5. Step 5: Solve for x
    x = 377,140.75/645.10
  6. Step 6: Final answer
    x = 584.63

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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.