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Finding the Fourth Proportional to 645.40, 968.20 and 212.42

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Solution

The fourth proportional to 645.40, 968.20 and 212.42 is: 318.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.40 : 968.20 = 212.42 : x
  2. Step 2: Convert to fraction form
    645.40/968.20 = 212.42/x
  3. Step 3: Cross multiply
    645.40x = 968.20 × 212.42
  4. Step 4: Simplify right side
    645.40x = 205,665.04
  5. Step 5: Solve for x
    x = 205,665.04/645.40
  6. Step 6: Final answer
    x = 318.66

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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.