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Finding the Fourth Proportional to 8.58, 12.80 and 7.98

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Solution

The fourth proportional to 8.58, 12.80 and 7.98 is: 11.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.58 : 12.80 = 7.98 : x
  2. Step 2: Convert to fraction form
    8.58/12.80 = 7.98/x
  3. Step 3: Cross multiply
    8.58x = 12.80 × 7.98
  4. Step 4: Simplify right side
    8.58x = 102.14
  5. Step 5: Solve for x
    x = 102.14/8.58
  6. Step 6: Final answer
    x = 11.90

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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.