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Finding the Fourth Proportional to 645.72, 890.64 and 449.28

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Solution

The fourth proportional to 645.72, 890.64 and 449.28 is: 619.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.72 : 890.64 = 449.28 : x
  2. Step 2: Convert to fraction form
    645.72/890.64 = 449.28/x
  3. Step 3: Cross multiply
    645.72x = 890.64 × 449.28
  4. Step 4: Simplify right side
    645.72x = 400,146.74
  5. Step 5: Solve for x
    x = 400,146.74/645.72
  6. Step 6: Final answer
    x = 619.69

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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.