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Finding the Fourth Proportional to 286.64, 430.03 and 81.21

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Solution

The fourth proportional to 286.64, 430.03 and 81.21 is: 121.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    286.64 : 430.03 = 81.21 : x
  2. Step 2: Convert to fraction form
    286.64/430.03 = 81.21/x
  3. Step 3: Cross multiply
    286.64x = 430.03 × 81.21
  4. Step 4: Simplify right side
    286.64x = 34,922.74
  5. Step 5: Solve for x
    x = 34,922.74/286.64
  6. Step 6: Final answer
    x = 121.83

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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.