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Finding the Fourth Proportional to 89.76, 123.81 and 85.74

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Solution

The fourth proportional to 89.76, 123.81 and 85.74 is: 118.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.76 : 123.81 = 85.74 : x
  2. Step 2: Convert to fraction form
    89.76/123.81 = 85.74/x
  3. Step 3: Cross multiply
    89.76x = 123.81 × 85.74
  4. Step 4: Simplify right side
    89.76x = 10,615.47
  5. Step 5: Solve for x
    x = 10,615.47/89.76
  6. Step 6: Final answer
    x = 118.27

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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.