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Finding the Fourth Proportional to 287.57, 431.28 and 141.21

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Solution

The fourth proportional to 287.57, 431.28 and 141.21 is: 211.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.57 : 431.28 = 141.21 : x
  2. Step 2: Convert to fraction form
    287.57/431.28 = 141.21/x
  3. Step 3: Cross multiply
    287.57x = 431.28 × 141.21
  4. Step 4: Simplify right side
    287.57x = 60,901.05
  5. Step 5: Solve for x
    x = 60,901.05/287.57
  6. Step 6: Final answer
    x = 211.78

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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.