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Finding the Fourth Proportional to 213.53, 320.18 and 69.21

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Solution

The fourth proportional to 213.53, 320.18 and 69.21 is: 103.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.53 : 320.18 = 69.21 : x
  2. Step 2: Convert to fraction form
    213.53/320.18 = 69.21/x
  3. Step 3: Cross multiply
    213.53x = 320.18 × 69.21
  4. Step 4: Simplify right side
    213.53x = 22,159.31
  5. Step 5: Solve for x
    x = 22,159.31/213.53
  6. Step 6: Final answer
    x = 103.78

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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.