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Finding the Fourth Proportional to 208.65, 287.96 and 115.40

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Solution

The fourth proportional to 208.65, 287.96 and 115.40 is: 159.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.65 : 287.96 = 115.40 : x
  2. Step 2: Convert to fraction form
    208.65/287.96 = 115.40/x
  3. Step 3: Cross multiply
    208.65x = 287.96 × 115.40
  4. Step 4: Simplify right side
    208.65x = 33,230.73
  5. Step 5: Solve for x
    x = 33,230.73/208.65
  6. Step 6: Final answer
    x = 159.26

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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.