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Finding the Fourth Proportional to 356.21, 491.42 and 257.79

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Solution

The fourth proportional to 356.21, 491.42 and 257.79 is: 355.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    356.21 : 491.42 = 257.79 : x
  2. Step 2: Convert to fraction form
    356.21/491.42 = 257.79/x
  3. Step 3: Cross multiply
    356.21x = 491.42 × 257.79
  4. Step 4: Simplify right side
    356.21x = 126,681.87
  5. Step 5: Solve for x
    x = 126,681.87/356.21
  6. Step 6: Final answer
    x = 355.64

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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.