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Finding the Fourth Proportional to 287.42, 431.08 and 81.99

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Solution

The fourth proportional to 287.42, 431.08 and 81.99 is: 122.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.42 : 431.08 = 81.99 : x
  2. Step 2: Convert to fraction form
    287.42/431.08 = 81.99/x
  3. Step 3: Cross multiply
    287.42x = 431.08 × 81.99
  4. Step 4: Simplify right side
    287.42x = 35,344.25
  5. Step 5: Solve for x
    x = 35,344.25/287.42
  6. Step 6: Final answer
    x = 122.97

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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.