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Finding the Fourth Proportional to 84.38, 125.79 and 79.21

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Solution

The fourth proportional to 84.38, 125.79 and 79.21 is: 118.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.38 : 125.79 = 79.21 : x
  2. Step 2: Convert to fraction form
    84.38/125.79 = 79.21/x
  3. Step 3: Cross multiply
    84.38x = 125.79 × 79.21
  4. Step 4: Simplify right side
    84.38x = 9,964.35
  5. Step 5: Solve for x
    x = 9,964.35/84.38
  6. Step 6: Final answer
    x = 118.10

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.