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Finding the Fourth Proportional to 285.65, 428.07 and 131.21

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Solution

The fourth proportional to 285.65, 428.07 and 131.21 is: 196.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.65 : 428.07 = 131.21 : x
  2. Step 2: Convert to fraction form
    285.65/428.07 = 131.21/x
  3. Step 3: Cross multiply
    285.65x = 428.07 × 131.21
  4. Step 4: Simplify right side
    285.65x = 56,164.92
  5. Step 5: Solve for x
    x = 56,164.92/285.65
  6. Step 6: Final answer
    x = 196.62

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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.