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Finding the Fourth Proportional to 101.42, 139.91 and 79.65

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Solution

The fourth proportional to 101.42, 139.91 and 79.65 is: 109.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.42 : 139.91 = 79.65 : x
  2. Step 2: Convert to fraction form
    101.42/139.91 = 79.65/x
  3. Step 3: Cross multiply
    101.42x = 139.91 × 79.65
  4. Step 4: Simplify right side
    101.42x = 11,143.83
  5. Step 5: Solve for x
    x = 11,143.83/101.42
  6. Step 6: Final answer
    x = 109.88

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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.