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Finding the Fourth Proportional to 645.44, 890.72 and 396.88

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Solution

The fourth proportional to 645.44, 890.72 and 396.88 is: 547.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.44 : 890.72 = 396.88 : x
  2. Step 2: Convert to fraction form
    645.44/890.72 = 396.88/x
  3. Step 3: Cross multiply
    645.44x = 890.72 × 396.88
  4. Step 4: Simplify right side
    645.44x = 353,508.95
  5. Step 5: Solve for x
    x = 353,508.95/645.44
  6. Step 6: Final answer
    x = 547.70

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1.5x scale

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.