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Finding the Fourth Proportional to 287.85, 397.15 and 189.64

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Solution

The fourth proportional to 287.85, 397.15 and 189.64 is: 261.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.85 : 397.15 = 189.64 : x
  2. Step 2: Convert to fraction form
    287.85/397.15 = 189.64/x
  3. Step 3: Cross multiply
    287.85x = 397.15 × 189.64
  4. Step 4: Simplify right side
    287.85x = 75,316.62
  5. Step 5: Solve for x
    x = 75,316.62/287.85
  6. Step 6: Final answer
    x = 261.65

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.