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Finding the Fourth Proportional to 287.43, 431.13 and 81.99

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Solution

The fourth proportional to 287.43, 431.13 and 81.99 is: 122.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.43 : 431.13 = 81.99 : x
  2. Step 2: Convert to fraction form
    287.43/431.13 = 81.99/x
  3. Step 3: Cross multiply
    287.43x = 431.13 × 81.99
  4. Step 4: Simplify right side
    287.43x = 35,348.35
  5. Step 5: Solve for x
    x = 35,348.35/287.43
  6. Step 6: Final answer
    x = 122.98

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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.