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Finding the Fourth Proportional to 285.20, 393.57 and 154.21

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Solution

The fourth proportional to 285.20, 393.57 and 154.21 is: 212.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.20 : 393.57 = 154.21 : x
  2. Step 2: Convert to fraction form
    285.20/393.57 = 154.21/x
  3. Step 3: Cross multiply
    285.20x = 393.57 × 154.21
  4. Step 4: Simplify right side
    285.20x = 60,690.65
  5. Step 5: Solve for x
    x = 60,690.65/285.20
  6. Step 6: Final answer
    x = 212.80

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.