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Finding the Fourth Proportional to 9.21, 12.68 and 7.84

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Solution

The fourth proportional to 9.21, 12.68 and 7.84 is: 10.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    9.21 : 12.68 = 7.84 : x
  2. Step 2: Convert to fraction form
    9.21/12.68 = 7.84/x
  3. Step 3: Cross multiply
    9.21x = 12.68 × 7.84
  4. Step 4: Simplify right side
    9.21x = 99.41
  5. Step 5: Solve for x
    x = 99.41/9.21
  6. Step 6: Final answer
    x = 10.79

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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.