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Finding the Fourth Proportional to 287.82, 431.72 and 71.39

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Solution

The fourth proportional to 287.82, 431.72 and 71.39 is: 107.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.82 : 431.72 = 71.39 : x
  2. Step 2: Convert to fraction form
    287.82/431.72 = 71.39/x
  3. Step 3: Cross multiply
    287.82x = 431.72 × 71.39
  4. Step 4: Simplify right side
    287.82x = 30,817.98
  5. Step 5: Solve for x
    x = 30,817.98/287.82
  6. Step 6: Final answer
    x = 107.07

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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.