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Finding the Fourth Proportional to 7.79, 10.72 and 7.11

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Solution

The fourth proportional to 7.79, 10.72 and 7.11 is: 9.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.79 : 10.72 = 7.11 : x
  2. Step 2: Convert to fraction form
    7.79/10.72 = 7.11/x
  3. Step 3: Cross multiply
    7.79x = 10.72 × 7.11
  4. Step 4: Simplify right side
    7.79x = 76.17
  5. Step 5: Solve for x
    x = 76.17/7.79
  6. Step 6: Final answer
    x = 9.78

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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.