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Finding the Fourth Proportional to 81.75, 112.78 and 53.74

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Solution

The fourth proportional to 81.75, 112.78 and 53.74 is: 74.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.75 : 112.78 = 53.74 : x
  2. Step 2: Convert to fraction form
    81.75/112.78 = 53.74/x
  3. Step 3: Cross multiply
    81.75x = 112.78 × 53.74
  4. Step 4: Simplify right side
    81.75x = 6,060.23
  5. Step 5: Solve for x
    x = 6,060.23/81.75
  6. Step 6: Final answer
    x = 74.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.