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Finding the Fourth Proportional to 287.75, 431.78 and 105.17

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Solution

The fourth proportional to 287.75, 431.78 and 105.17 is: 157.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.75 : 431.78 = 105.17 : x
  2. Step 2: Convert to fraction form
    287.75/431.78 = 105.17/x
  3. Step 3: Cross multiply
    287.75x = 431.78 × 105.17
  4. Step 4: Simplify right side
    287.75x = 45,407.62
  5. Step 5: Solve for x
    x = 45,407.62/287.75
  6. Step 6: Final answer
    x = 157.80

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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.