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Finding the Fourth Proportional to 12.80, 17.64 and 9.15

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Solution

The fourth proportional to 12.80, 17.64 and 9.15 is: 12.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.80 : 17.64 = 9.15 : x
  2. Step 2: Convert to fraction form
    12.80/17.64 = 9.15/x
  3. Step 3: Cross multiply
    12.80x = 17.64 × 9.15
  4. Step 4: Simplify right side
    12.80x = 161.41
  5. Step 5: Solve for x
    x = 161.41/12.80
  6. Step 6: Final answer
    x = 12.61

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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.