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Finding the Fourth Proportional to 386.76, 580.40 and 213.60

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Solution

The fourth proportional to 386.76, 580.40 and 213.60 is: 320.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.76 : 580.40 = 213.60 : x
  2. Step 2: Convert to fraction form
    386.76/580.40 = 213.60/x
  3. Step 3: Cross multiply
    386.76x = 580.40 × 213.60
  4. Step 4: Simplify right side
    386.76x = 123,973.44
  5. Step 5: Solve for x
    x = 123,973.44/386.76
  6. Step 6: Final answer
    x = 320.54

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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.