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Finding the Fourth Proportional to 81.07, 121.35 and 53.66

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Solution

The fourth proportional to 81.07, 121.35 and 53.66 is: 80.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.07 : 121.35 = 53.66 : x
  2. Step 2: Convert to fraction form
    81.07/121.35 = 53.66/x
  3. Step 3: Cross multiply
    81.07x = 121.35 × 53.66
  4. Step 4: Simplify right side
    81.07x = 6,511.64
  5. Step 5: Solve for x
    x = 6,511.64/81.07
  6. Step 6: Final answer
    x = 80.32

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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.