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Finding the Fourth Proportional to 325.20, 488.40 and 257.40

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Solution

The fourth proportional to 325.20, 488.40 and 257.40 is: 386.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    325.20 : 488.40 = 257.40 : x
  2. Step 2: Convert to fraction form
    325.20/488.40 = 257.40/x
  3. Step 3: Cross multiply
    325.20x = 488.40 × 257.40
  4. Step 4: Simplify right side
    325.20x = 125,714.16
  5. Step 5: Solve for x
    x = 125,714.16/325.20
  6. Step 6: Final answer
    x = 386.57

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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.