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Finding the Fourth Proportional to 812.49, 1,218.12 and 421.96

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Solution

The fourth proportional to 812.49, 1,218.12 and 421.96 is: 632.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.49 : 1,218.12 = 421.96 : x
  2. Step 2: Convert to fraction form
    812.49/1,218.12 = 421.96/x
  3. Step 3: Cross multiply
    812.49x = 1,218.12 × 421.96
  4. Step 4: Simplify right side
    812.49x = 513,997.92
  5. Step 5: Solve for x
    x = 513,997.92/812.49
  6. Step 6: Final answer
    x = 632.62

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Double scale
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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.