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Finding the Fourth Proportional to 311.36, 429.76 and 208.08

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Solution

The fourth proportional to 311.36, 429.76 and 208.08 is: 287.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.36 : 429.76 = 208.08 : x
  2. Step 2: Convert to fraction form
    311.36/429.76 = 208.08/x
  3. Step 3: Cross multiply
    311.36x = 429.76 × 208.08
  4. Step 4: Simplify right side
    311.36x = 89,424.46
  5. Step 5: Solve for x
    x = 89,424.46/311.36
  6. Step 6: Final answer
    x = 287.21

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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.