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Finding the Fourth Proportional to 208.42, 287.70 and 138.54

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Solution

The fourth proportional to 208.42, 287.70 and 138.54 is: 191.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.42 : 287.70 = 138.54 : x
  2. Step 2: Convert to fraction form
    208.42/287.70 = 138.54/x
  3. Step 3: Cross multiply
    208.42x = 287.70 × 138.54
  4. Step 4: Simplify right side
    208.42x = 39,857.96
  5. Step 5: Solve for x
    x = 39,857.96/208.42
  6. Step 6: Final answer
    x = 191.24

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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.