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Finding the Fourth Proportional to 287.20, 396.08 and 231.60

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Solution

The fourth proportional to 287.20, 396.08 and 231.60 is: 319.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.20 : 396.08 = 231.60 : x
  2. Step 2: Convert to fraction form
    287.20/396.08 = 231.60/x
  3. Step 3: Cross multiply
    287.20x = 396.08 × 231.60
  4. Step 4: Simplify right side
    287.20x = 91,732.13
  5. Step 5: Solve for x
    x = 91,732.13/287.20
  6. Step 6: Final answer
    x = 319.40

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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.