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Finding the Fourth Proportional to 143.78, 215.79 and 71.72

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Solution

The fourth proportional to 143.78, 215.79 and 71.72 is: 107.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.78 : 215.79 = 71.72 : x
  2. Step 2: Convert to fraction form
    143.78/215.79 = 71.72/x
  3. Step 3: Cross multiply
    143.78x = 215.79 × 71.72
  4. Step 4: Simplify right side
    143.78x = 15,476.46
  5. Step 5: Solve for x
    x = 15,476.46/143.78
  6. Step 6: Final answer
    x = 107.64

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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.