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Finding the Fourth Proportional to 287.25, 430.89 and 81.81

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Solution

The fourth proportional to 287.25, 430.89 and 81.81 is: 122.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.25 : 430.89 = 81.81 : x
  2. Step 2: Convert to fraction form
    287.25/430.89 = 81.81/x
  3. Step 3: Cross multiply
    287.25x = 430.89 × 81.81
  4. Step 4: Simplify right side
    287.25x = 35,250.80
  5. Step 5: Solve for x
    x = 35,250.80/287.25
  6. Step 6: Final answer
    x = 122.72

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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.