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Finding the Fourth Proportional to 8.55, 12.80 and 7.74

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Solution

The fourth proportional to 8.55, 12.80 and 7.74 is: 11.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.55 : 12.80 = 7.74 : x
  2. Step 2: Convert to fraction form
    8.55/12.80 = 7.74/x
  3. Step 3: Cross multiply
    8.55x = 12.80 × 7.74
  4. Step 4: Simplify right side
    8.55x = 99.03
  5. Step 5: Solve for x
    x = 99.03/8.55
  6. Step 6: Final answer
    x = 11.58

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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.