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Finding the Fourth Proportional to 208.70, 287.98 and 115.43

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Solution

The fourth proportional to 208.70, 287.98 and 115.43 is: 159.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.70 : 287.98 = 115.43 : x
  2. Step 2: Convert to fraction form
    208.70/287.98 = 115.43/x
  3. Step 3: Cross multiply
    208.70x = 287.98 × 115.43
  4. Step 4: Simplify right side
    208.70x = 33,241.46
  5. Step 5: Solve for x
    x = 33,241.46/208.70
  6. Step 6: Final answer
    x = 159.28

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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.