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Finding the Fourth Proportional to 143.82, 215.21 and 86.07

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Solution

The fourth proportional to 143.82, 215.21 and 86.07 is: 128.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.82 : 215.21 = 86.07 : x
  2. Step 2: Convert to fraction form
    143.82/215.21 = 86.07/x
  3. Step 3: Cross multiply
    143.82x = 215.21 × 86.07
  4. Step 4: Simplify right side
    143.82x = 18,522.69
  5. Step 5: Solve for x
    x = 18,522.69/143.82
  6. Step 6: Final answer
    x = 128.79

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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.