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Finding the Fourth Proportional to 306.90, 423.18 and 208.71

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Solution

The fourth proportional to 306.90, 423.18 and 208.71 is: 287.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    306.90 : 423.18 = 208.71 : x
  2. Step 2: Convert to fraction form
    306.90/423.18 = 208.71/x
  3. Step 3: Cross multiply
    306.90x = 423.18 × 208.71
  4. Step 4: Simplify right side
    306.90x = 88,321.90
  5. Step 5: Solve for x
    x = 88,321.90/306.90
  6. Step 6: Final answer
    x = 287.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.