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Finding the Fourth Proportional to 390.81, 539.70 and 298.20

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Solution

The fourth proportional to 390.81, 539.70 and 298.20 is: 411.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.81 : 539.70 = 298.20 : x
  2. Step 2: Convert to fraction form
    390.81/539.70 = 298.20/x
  3. Step 3: Cross multiply
    390.81x = 539.70 × 298.20
  4. Step 4: Simplify right side
    390.81x = 160,938.54
  5. Step 5: Solve for x
    x = 160,938.54/390.81
  6. Step 6: Final answer
    x = 411.81

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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.