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Finding the Fourth Proportional to 389.25, 581.81 and 320.40

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Solution

The fourth proportional to 389.25, 581.81 and 320.40 is: 478.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.25 : 581.81 = 320.40 : x
  2. Step 2: Convert to fraction form
    389.25/581.81 = 320.40/x
  3. Step 3: Cross multiply
    389.25x = 581.81 × 320.40
  4. Step 4: Simplify right side
    389.25x = 186,410.32
  5. Step 5: Solve for x
    x = 186,410.32/389.25
  6. Step 6: Final answer
    x = 478.90

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.