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Finding the Fourth Proportional to 81.36, 121.52 and 79.84

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Solution

The fourth proportional to 81.36, 121.52 and 79.84 is: 119.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.36 : 121.52 = 79.84 : x
  2. Step 2: Convert to fraction form
    81.36/121.52 = 79.84/x
  3. Step 3: Cross multiply
    81.36x = 121.52 × 79.84
  4. Step 4: Simplify right side
    81.36x = 9,702.16
  5. Step 5: Solve for x
    x = 9,702.16/81.36
  6. Step 6: Final answer
    x = 119.25

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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.