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Finding the Fourth Proportional to 213.78, 320.61 and 145.28

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Solution

The fourth proportional to 213.78, 320.61 and 145.28 is: 217.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.78 : 320.61 = 145.28 : x
  2. Step 2: Convert to fraction form
    213.78/320.61 = 145.28/x
  3. Step 3: Cross multiply
    213.78x = 320.61 × 145.28
  4. Step 4: Simplify right side
    213.78x = 46,578.22
  5. Step 5: Solve for x
    x = 46,578.22/213.78
  6. Step 6: Final answer
    x = 217.88

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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.