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Finding the Fourth Proportional to 8.65, 12.90 and 8.56

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Solution

The fourth proportional to 8.65, 12.90 and 8.56 is: 12.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.65 : 12.90 = 8.56 : x
  2. Step 2: Convert to fraction form
    8.65/12.90 = 8.56/x
  3. Step 3: Cross multiply
    8.65x = 12.90 × 8.56
  4. Step 4: Simplify right side
    8.65x = 110.38
  5. Step 5: Solve for x
    x = 110.38/8.65
  6. Step 6: Final answer
    x = 12.76

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.