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Finding the Fourth Proportional to 390.30, 585.75 and 207.75

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Solution

The fourth proportional to 390.30, 585.75 and 207.75 is: 311.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.30 : 585.75 = 207.75 : x
  2. Step 2: Convert to fraction form
    390.30/585.75 = 207.75/x
  3. Step 3: Cross multiply
    390.30x = 585.75 × 207.75
  4. Step 4: Simplify right side
    390.30x = 121,689.56
  5. Step 5: Solve for x
    x = 121,689.56/390.30
  6. Step 6: Final answer
    x = 311.78

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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.