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Finding the Fourth Proportional to 306.40, 422.49 and 208.21

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Solution

The fourth proportional to 306.40, 422.49 and 208.21 is: 287.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    306.40 : 422.49 = 208.21 : x
  2. Step 2: Convert to fraction form
    306.40/422.49 = 208.21/x
  3. Step 3: Cross multiply
    306.40x = 422.49 × 208.21
  4. Step 4: Simplify right side
    306.40x = 87,966.64
  5. Step 5: Solve for x
    x = 87,966.64/306.40
  6. Step 6: Final answer
    x = 287.10

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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.