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Finding the Fourth Proportional to 390.74, 585 and 207.72

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Solution

The fourth proportional to 390.74, 585 and 207.72 is: 310.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.74 : 585 = 207.72 : x
  2. Step 2: Convert to fraction form
    390.74/585 = 207.72/x
  3. Step 3: Cross multiply
    390.74x = 585 × 207.72
  4. Step 4: Simplify right side
    390.74x = 121,516.20
  5. Step 5: Solve for x
    x = 121,516.20/390.74
  6. Step 6: Final answer
    x = 310.99

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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.