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Finding the Fourth Proportional to 213.68, 320.28 and 85.28

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Solution

The fourth proportional to 213.68, 320.28 and 85.28 is: 127.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.68 : 320.28 = 85.28 : x
  2. Step 2: Convert to fraction form
    213.68/320.28 = 85.28/x
  3. Step 3: Cross multiply
    213.68x = 320.28 × 85.28
  4. Step 4: Simplify right side
    213.68x = 27,313.48
  5. Step 5: Solve for x
    x = 27,313.48/213.68
  6. Step 6: Final answer
    x = 127.82

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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.