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Finding the Fourth Proportional to 143.25, 215.29 and 85.49

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Solution

The fourth proportional to 143.25, 215.29 and 85.49 is: 128.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.25 : 215.29 = 85.49 : x
  2. Step 2: Convert to fraction form
    143.25/215.29 = 85.49/x
  3. Step 3: Cross multiply
    143.25x = 215.29 × 85.49
  4. Step 4: Simplify right side
    143.25x = 18,405.14
  5. Step 5: Solve for x
    x = 18,405.14/143.25
  6. Step 6: Final answer
    x = 128.48

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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.