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Finding the Fourth Proportional to 287.35, 430.92 and 81.91

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Solution

The fourth proportional to 287.35, 430.92 and 81.91 is: 122.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.35 : 430.92 = 81.91 : x
  2. Step 2: Convert to fraction form
    287.35/430.92 = 81.91/x
  3. Step 3: Cross multiply
    287.35x = 430.92 × 81.91
  4. Step 4: Simplify right side
    287.35x = 35,297.20
  5. Step 5: Solve for x
    x = 35,297.20/287.35
  6. Step 6: Final answer
    x = 122.84

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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.