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Finding the Fourth Proportional to 390.91, 586.08 and 208.39

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Solution

The fourth proportional to 390.91, 586.08 and 208.39 is: 312.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.91 : 586.08 = 208.39 : x
  2. Step 2: Convert to fraction form
    390.91/586.08 = 208.39/x
  3. Step 3: Cross multiply
    390.91x = 586.08 × 208.39
  4. Step 4: Simplify right side
    390.91x = 122,133.21
  5. Step 5: Solve for x
    x = 122,133.21/390.91
  6. Step 6: Final answer
    x = 312.43

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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.