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Finding the Fourth Proportional to 257.58, 386.38 and 65.21

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Solution

The fourth proportional to 257.58, 386.38 and 65.21 is: 97.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.58 : 386.38 = 65.21 : x
  2. Step 2: Convert to fraction form
    257.58/386.38 = 65.21/x
  3. Step 3: Cross multiply
    257.58x = 386.38 × 65.21
  4. Step 4: Simplify right side
    257.58x = 25,193.74
  5. Step 5: Solve for x
    x = 25,193.74/257.58
  6. Step 6: Final answer
    x = 97.81

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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.