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Finding the Fourth Proportional to 285.48, 428.19 and 213.78

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Solution

The fourth proportional to 285.48, 428.19 and 213.78 is: 320.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.48 : 428.19 = 213.78 : x
  2. Step 2: Convert to fraction form
    285.48/428.19 = 213.78/x
  3. Step 3: Cross multiply
    285.48x = 428.19 × 213.78
  4. Step 4: Simplify right side
    285.48x = 91,538.46
  5. Step 5: Solve for x
    x = 91,538.46/285.48
  6. Step 6: Final answer
    x = 320.65

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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.