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Finding the Fourth Proportional to 8.49, 12.69 and 7.80

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Solution

The fourth proportional to 8.49, 12.69 and 7.80 is: 11.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.49 : 12.69 = 7.80 : x
  2. Step 2: Convert to fraction form
    8.49/12.69 = 7.80/x
  3. Step 3: Cross multiply
    8.49x = 12.69 × 7.80
  4. Step 4: Simplify right side
    8.49x = 98.98
  5. Step 5: Solve for x
    x = 98.98/8.49
  6. Step 6: Final answer
    x = 11.66

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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.