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Finding the Fourth Proportional to 390.56, 539.75 and 320.51

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Solution

The fourth proportional to 390.56, 539.75 and 320.51 is: 442.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.56 : 539.75 = 320.51 : x
  2. Step 2: Convert to fraction form
    390.56/539.75 = 320.51/x
  3. Step 3: Cross multiply
    390.56x = 539.75 × 320.51
  4. Step 4: Simplify right side
    390.56x = 172,990.97
  5. Step 5: Solve for x
    x = 172,990.97/390.56
  6. Step 6: Final answer
    x = 442.94

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.