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Finding the Fourth Proportional to 79.85, 119.78 and 28.51

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Solution

The fourth proportional to 79.85, 119.78 and 28.51 is: 42.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.85 : 119.78 = 28.51 : x
  2. Step 2: Convert to fraction form
    79.85/119.78 = 28.51/x
  3. Step 3: Cross multiply
    79.85x = 119.78 × 28.51
  4. Step 4: Simplify right side
    79.85x = 3,414.93
  5. Step 5: Solve for x
    x = 3,414.93/79.85
  6. Step 6: Final answer
    x = 42.77

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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.