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Finding the Fourth Proportional to 390.15, 584.55 and 207.90

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Solution

The fourth proportional to 390.15, 584.55 and 207.90 is: 311.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.15 : 584.55 = 207.90 : x
  2. Step 2: Convert to fraction form
    390.15/584.55 = 207.90/x
  3. Step 3: Cross multiply
    390.15x = 584.55 × 207.90
  4. Step 4: Simplify right side
    390.15x = 121,527.95
  5. Step 5: Solve for x
    x = 121,527.95/390.15
  6. Step 6: Final answer
    x = 311.49

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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.