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Finding the Fourth Proportional to 645.59, 968.42 and 212.78

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Solution

The fourth proportional to 645.59, 968.42 and 212.78 is: 319.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.59 : 968.42 = 212.78 : x
  2. Step 2: Convert to fraction form
    645.59/968.42 = 212.78/x
  3. Step 3: Cross multiply
    645.59x = 968.42 × 212.78
  4. Step 4: Simplify right side
    645.59x = 206,063.36
  5. Step 5: Solve for x
    x = 206,063.36/645.59
  6. Step 6: Final answer
    x = 319.18

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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.