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Finding the Fourth Proportional to 645.76, 968.42 and 212.81

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Solution

The fourth proportional to 645.76, 968.42 and 212.81 is: 319.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.76 : 968.42 = 212.81 : x
  2. Step 2: Convert to fraction form
    645.76/968.42 = 212.81/x
  3. Step 3: Cross multiply
    645.76x = 968.42 × 212.81
  4. Step 4: Simplify right side
    645.76x = 206,089.46
  5. Step 5: Solve for x
    x = 206,089.46/645.76
  6. Step 6: Final answer
    x = 319.14

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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.