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Finding the Fourth Proportional to 390.64, 539.06 and 215.97

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Solution

The fourth proportional to 390.64, 539.06 and 215.97 is: 298.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 539.06 = 215.97 : x
  2. Step 2: Convert to fraction form
    390.64/539.06 = 215.97/x
  3. Step 3: Cross multiply
    390.64x = 539.06 × 215.97
  4. Step 4: Simplify right side
    390.64x = 116,420.25
  5. Step 5: Solve for x
    x = 116,420.25/390.64
  6. Step 6: Final answer
    x = 298.03

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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.