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Finding the Fourth Proportional to 390.87, 586.59 and 208.30

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Solution

The fourth proportional to 390.87, 586.59 and 208.30 is: 312.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.87 : 586.59 = 208.30 : x
  2. Step 2: Convert to fraction form
    390.87/586.59 = 208.30/x
  3. Step 3: Cross multiply
    390.87x = 586.59 × 208.30
  4. Step 4: Simplify right side
    390.87x = 122,186.70
  5. Step 5: Solve for x
    x = 122,186.70/390.87
  6. Step 6: Final answer
    x = 312.60

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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.