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Finding the Fourth Proportional to 390.79, 539.31 and 216.19

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Solution

The fourth proportional to 390.79, 539.31 and 216.19 is: 298.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.79 : 539.31 = 216.19 : x
  2. Step 2: Convert to fraction form
    390.79/539.31 = 216.19/x
  3. Step 3: Cross multiply
    390.79x = 539.31 × 216.19
  4. Step 4: Simplify right side
    390.79x = 116,593.43
  5. Step 5: Solve for x
    x = 116,593.43/390.79
  6. Step 6: Final answer
    x = 298.35

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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.