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Finding the Fourth Proportional to 812.81, 1,217.46 and 427.25

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Solution

The fourth proportional to 812.81, 1,217.46 and 427.25 is: 639.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.81 : 1,217.46 = 427.25 : x
  2. Step 2: Convert to fraction form
    812.81/1,217.46 = 427.25/x
  3. Step 3: Cross multiply
    812.81x = 1,217.46 × 427.25
  4. Step 4: Simplify right side
    812.81x = 520,159.79
  5. Step 5: Solve for x
    x = 520,159.79/812.81
  6. Step 6: Final answer
    x = 639.95

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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.