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Finding the Fourth Proportional to 287.28, 430.88 and 257.12

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Solution

The fourth proportional to 287.28, 430.88 and 257.12 is: 385.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.28 : 430.88 = 257.12 : x
  2. Step 2: Convert to fraction form
    287.28/430.88 = 257.12/x
  3. Step 3: Cross multiply
    287.28x = 430.88 × 257.12
  4. Step 4: Simplify right side
    287.28x = 110,787.87
  5. Step 5: Solve for x
    x = 110,787.87/287.28
  6. Step 6: Final answer
    x = 385.64

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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.