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Finding the Fourth Proportional to 287.61, 431.43 and 82.18

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Solution

The fourth proportional to 287.61, 431.43 and 82.18 is: 123.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.61 : 431.43 = 82.18 : x
  2. Step 2: Convert to fraction form
    287.61/431.43 = 82.18/x
  3. Step 3: Cross multiply
    287.61x = 431.43 × 82.18
  4. Step 4: Simplify right side
    287.61x = 35,455.96
  5. Step 5: Solve for x
    x = 35,455.96/287.61
  6. Step 6: Final answer
    x = 123.28

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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.