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Finding the Fourth Proportional to 84.36, 125.40 and 80.64

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Solution

The fourth proportional to 84.36, 125.40 and 80.64 is: 119.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.36 : 125.40 = 80.64 : x
  2. Step 2: Convert to fraction form
    84.36/125.40 = 80.64/x
  3. Step 3: Cross multiply
    84.36x = 125.40 × 80.64
  4. Step 4: Simplify right side
    84.36x = 10,112.26
  5. Step 5: Solve for x
    x = 10,112.26/84.36
  6. Step 6: Final answer
    x = 119.87

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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.