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Finding the Fourth Proportional to 212.72, 319.28 and 84.48

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Solution

The fourth proportional to 212.72, 319.28 and 84.48 is: 126.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.72 : 319.28 = 84.48 : x
  2. Step 2: Convert to fraction form
    212.72/319.28 = 84.48/x
  3. Step 3: Cross multiply
    212.72x = 319.28 × 84.48
  4. Step 4: Simplify right side
    212.72x = 26,972.77
  5. Step 5: Solve for x
    x = 26,972.77/212.72
  6. Step 6: Final answer
    x = 126.80

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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.