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Finding the Fourth Proportional to 645.26, 890.76 and 396.79

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Solution

The fourth proportional to 645.26, 890.76 and 396.79 is: 547.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.26 : 890.76 = 396.79 : x
  2. Step 2: Convert to fraction form
    645.26/890.76 = 396.79/x
  3. Step 3: Cross multiply
    645.26x = 890.76 × 396.79
  4. Step 4: Simplify right side
    645.26x = 353,440.21
  5. Step 5: Solve for x
    x = 353,440.21/645.26
  6. Step 6: Final answer
    x = 547.75

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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.