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Finding the Fourth Proportional to 258.42, 387.96 and 172.30

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Solution

The fourth proportional to 258.42, 387.96 and 172.30 is: 258.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.42 : 387.96 = 172.30 : x
  2. Step 2: Convert to fraction form
    258.42/387.96 = 172.30/x
  3. Step 3: Cross multiply
    258.42x = 387.96 × 172.30
  4. Step 4: Simplify right side
    258.42x = 66,847.16
  5. Step 5: Solve for x
    x = 66,847.16/258.42
  6. Step 6: Final answer
    x = 258.68

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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.