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Finding the Fourth Proportional to 12.99, 19.47 and 7.91

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Solution

The fourth proportional to 12.99, 19.47 and 7.91 is: 11.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.99 : 19.47 = 7.91 : x
  2. Step 2: Convert to fraction form
    12.99/19.47 = 7.91/x
  3. Step 3: Cross multiply
    12.99x = 19.47 × 7.91
  4. Step 4: Simplify right side
    12.99x = 154.01
  5. Step 5: Solve for x
    x = 154.01/12.99
  6. Step 6: Final answer
    x = 11.86

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.