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Finding the Fourth Proportional to 287.72, 397.34 and 257.18

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Solution

The fourth proportional to 287.72, 397.34 and 257.18 is: 355.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.72 : 397.34 = 257.18 : x
  2. Step 2: Convert to fraction form
    287.72/397.34 = 257.18/x
  3. Step 3: Cross multiply
    287.72x = 397.34 × 257.18
  4. Step 4: Simplify right side
    287.72x = 102,187.90
  5. Step 5: Solve for x
    x = 102,187.90/287.72
  6. Step 6: Final answer
    x = 355.16

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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.