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Finding the Fourth Proportional to 645.48, 890.79 and 396.95

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Solution

The fourth proportional to 645.48, 890.79 and 396.95 is: 547.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.48 : 890.79 = 396.95 : x
  2. Step 2: Convert to fraction form
    645.48/890.79 = 396.95/x
  3. Step 3: Cross multiply
    645.48x = 890.79 × 396.95
  4. Step 4: Simplify right side
    645.48x = 353,596.49
  5. Step 5: Solve for x
    x = 353,596.49/645.48
  6. Step 6: Final answer
    x = 547.80

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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.