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Finding the Fourth Proportional to 386.86, 579.20 and 319.20

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Solution

The fourth proportional to 386.86, 579.20 and 319.20 is: 477.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.86 : 579.20 = 319.20 : x
  2. Step 2: Convert to fraction form
    386.86/579.20 = 319.20/x
  3. Step 3: Cross multiply
    386.86x = 579.20 × 319.20
  4. Step 4: Simplify right side
    386.86x = 184,880.64
  5. Step 5: Solve for x
    x = 184,880.64/386.86
  6. Step 6: Final answer
    x = 477.90

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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.