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Finding the Fourth Proportional to 390.24, 585.20 and 207.60

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Solution

The fourth proportional to 390.24, 585.20 and 207.60 is: 311.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.24 : 585.20 = 207.60 : x
  2. Step 2: Convert to fraction form
    390.24/585.20 = 207.60/x
  3. Step 3: Cross multiply
    390.24x = 585.20 × 207.60
  4. Step 4: Simplify right side
    390.24x = 121,486.48
  5. Step 5: Solve for x
    x = 121,486.48/390.24
  6. Step 6: Final answer
    x = 311.31

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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.