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Finding the Fourth Proportional to 665.28, 996.55 and 390.71

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Solution

The fourth proportional to 665.28, 996.55 and 390.71 is: 585.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.28 : 996.55 = 390.71 : x
  2. Step 2: Convert to fraction form
    665.28/996.55 = 390.71/x
  3. Step 3: Cross multiply
    665.28x = 996.55 × 390.71
  4. Step 4: Simplify right side
    665.28x = 389,362.05
  5. Step 5: Solve for x
    x = 389,362.05/665.28
  6. Step 6: Final answer
    x = 585.26

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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.