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Finding the Fourth Proportional to 119.91, 165.39 and 78.47

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Solution

The fourth proportional to 119.91, 165.39 and 78.47 is: 108.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    119.91 : 165.39 = 78.47 : x
  2. Step 2: Convert to fraction form
    119.91/165.39 = 78.47/x
  3. Step 3: Cross multiply
    119.91x = 165.39 × 78.47
  4. Step 4: Simplify right side
    119.91x = 12,978.09
  5. Step 5: Solve for x
    x = 12,978.09/119.91
  6. Step 6: Final answer
    x = 108.24

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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.