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Finding the Fourth Proportional to 287.45, 428.78 and 254.64

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Solution

The fourth proportional to 287.45, 428.78 and 254.64 is: 379.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.45 : 428.78 = 254.64 : x
  2. Step 2: Convert to fraction form
    287.45/428.78 = 254.64/x
  3. Step 3: Cross multiply
    287.45x = 428.78 × 254.64
  4. Step 4: Simplify right side
    287.45x = 109,183.27
  5. Step 5: Solve for x
    x = 109,183.27/287.45
  6. Step 6: Final answer
    x = 379.84

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.