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Finding the Fourth Proportional to 645.30, 890.43 and 396.56

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Solution

The fourth proportional to 645.30, 890.43 and 396.56 is: 547.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.30 : 890.43 = 396.56 : x
  2. Step 2: Convert to fraction form
    645.30/890.43 = 396.56/x
  3. Step 3: Cross multiply
    645.30x = 890.43 × 396.56
  4. Step 4: Simplify right side
    645.30x = 353,109.66
  5. Step 5: Solve for x
    x = 353,109.66/645.30
  6. Step 6: Final answer
    x = 547.20

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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.