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Finding the Fourth Proportional to 9, 12.39 and 8.16

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Solution

The fourth proportional to 9, 12.39 and 8.16 is: 11.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    9 : 12.39 = 8.16 : x
  2. Step 2: Convert to fraction form
    9/12.39 = 8.16/x
  3. Step 3: Cross multiply
    9x = 12.39 × 8.16
  4. Step 4: Simplify right side
    9x = 101.10
  5. Step 5: Solve for x
    x = 101.10/9
  6. Step 6: Final answer
    x = 11.23

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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.