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Finding the Fourth Proportional to 7.78, 10.74 and 7.09

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Solution

The fourth proportional to 7.78, 10.74 and 7.09 is: 9.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.78 : 10.74 = 7.09 : x
  2. Step 2: Convert to fraction form
    7.78/10.74 = 7.09/x
  3. Step 3: Cross multiply
    7.78x = 10.74 × 7.09
  4. Step 4: Simplify right side
    7.78x = 76.15
  5. Step 5: Solve for x
    x = 76.15/7.78
  6. Step 6: Final answer
    x = 9.79

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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.