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Finding the Fourth Proportional to 84.74, 126.81 and 71.78

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Solution

The fourth proportional to 84.74, 126.81 and 71.78 is: 107.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.74 : 126.81 = 71.78 : x
  2. Step 2: Convert to fraction form
    84.74/126.81 = 71.78/x
  3. Step 3: Cross multiply
    84.74x = 126.81 × 71.78
  4. Step 4: Simplify right side
    84.74x = 9,101.79
  5. Step 5: Solve for x
    x = 9,101.79/84.74
  6. Step 6: Final answer
    x = 107.41

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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.